This is the reply I got from my email to Don Wittenberger. I sent a follow-up email and asked if I could share his answer.
Here is his email:
When Larry Horton, the original owner of Rivendell Mountain Works, went bankrupt in 1981, I purchased the Rivendell assets from the bankruptcy court and went to Victor, Idaho, with a rental truck to retrieve the patterns, inventory, equipment, etc. I have been the sole owner of Rivendell Mountain Works ever since, and the original Bombshelter Tent patterns are currently stored in my home.
Eric Hardee and I have known each other for over 25 years, and he worked with me for many years to restart limited production of Jensen Packs. He now makes a few packs for public sale, using the original patterns, under a licensing agreement.
The tent is a more difficult nut to crack. It has some non-standard components that must be custom-sourced in commercial quantities (for example, the poles must be custom manufactured), which requires a substantial financial investment up front. Another obstacle has been the amount of time and work a project of this scope requires, which wasn't practical when I was working full time.
Now that I'm retired, and have income beyond our family's needs, reviving the tent is more feasible. There are, however, a number of preliminary things that have to be done. Some of the wood patterns are damaged and must be replaced. Hot cutting the fabric can't be done in the basement or garage because of the fumes; I'll have to build a shed to house a cutting table. (This is a problem for Eric, too.) Possibly prototyping work can begin next year, but an initial production run of tents for public sale is still at least a couple years away. I expect my production methodology to mimic Horton's in the 1970s, that is, the tents will be made one at a time, which means if someone wants to use a special fabric or wants custom features, that can be done, as long as my cutting and sewing equipment will handle the special fabric. The one thing I plan to do differently is that Horton didn't stock the tents and didn't make them until an order came in, whereas I plan to make a standardized product and keep several in inventory. However, even in this modus operandi, customizing requests could be accomodated.
I am, however, a proponent of a simple standard version of this tent, using the original design that had sidewalls of ordinary ripstop and a coated nylon rainfly. I have no plans to produce a Gore-Tex version. Although Horton made a few Gore-Tex Bombshelter Tents toward the end, I think he did this more to get on the Gore-Tex bandwagon than for practical reasons. From a design standpoint, I don't like the Gore-Tex idea, and try to steer people away from it, for a couple of reasons. One, the rainfly does much more than keep rain out. It stiffens the entire structure considerably, so you'll want to use the fly if strong winds are encountered, no matter what material the sidewalls are made of. It's true Don Jensen never used a fly and didn't design one (it was designed by Larry Horton), but Jensen was climbing in Alaska, where the mountain environment is arid and what precipitation there is falls as snow, so he didn't need one. This environment is more or less unique to Alaska, and almost everywhere else you'll need a fly. Second, plain ripstop breathes better than Gore-Tex, so you get less condensation.
I think the same considerations apply to exotic fabrics such as Cuben. You want to ask yourself what your reason is for using such a material. If the objective is to save weight or bulk, the savings will be minimal. The floor, poles, and fly comprise about 2/3rds of the weight and bulk of the tent; if you make the sidewalls of a fabric weighing a third as much as ripstop, you'll hardly notice the difference because you're saving less than 10% of the total weight of the tent. Once things are up and running, I'd be willing to consider making tents of special fabrics on request, but I think people should really think this through first. Another point to consider is that, in terms of strength, any failure is much more likely to be at the seams than the fabric tearing, and when you use a super-high-strength fabric made from very thin threads, there's not much for the thread to grip and no matter what the tear strength of the fabric is, this approach could significantly weaken the seams. You need a certain amount of fabric bulk to maintain seam strength.
I've spent 28 years thinking about this kind of stuff, and I really feel keeping it simple and sticking to plain materials is the way to go, not only to keep costs down, but for functional reasons as well. The materials and scantlings of the original tent are proven to work, and I'm very reluctant to fiddle with them. The axiom, "If it ain't broke, don't fix it," applies here.
The Bombshelter is a specialized tent. It's smaller than typical two-person tents, does not have the headroom of a dome or geodesic design, and is not free standing. I wouldn't call it a "survival tent" but it was designed for, and works in, extreme mountaineering conditions. It is specially designed to withstand strong winds. Almost any general backpacking tent is more comfortable, as the Bombshelter is a squeeze for two average-sized people. It originally required 11 stakes, but I figured out a simple trick that reduces this to 9 stakes. I'm looking at a possible way to increase headroom at the middle of the tent, where you sit up, without modifying the patterns but it's not fully worked out yet.
Before someone took on the task of trying to make a Bombshelter themselves, I would offer the following cautions. First, you need a pole set. I can't supply one; I have a few individual pole pieces, but not enough to make up a complete pole set. The assembly is highly complex. The tent is not as simple as it looks. There are dozens of fabric pieces, and nearly 200 individual components total. The pieces have to go together in a certain sequence, or you'll never get the thing together. The assembly sequence was never written down, or at least, I couldn't find any instructions in Victor, and I have yet to work out all the details of the precise sequence, although I more or less know what the general sequence is. It's complicated and there are dozens of steps, and you can't get them out of order. You also need commercial grade sewing equipment; there are many places where you have to sew through multiple layers of fabric and webbing, and a home sewing machine can't handle it. The tent also requires professional-class sewing skills; there several teams of seams, including felled seams along curving lines, that require much practice and are beyond the abilities of most amateur seamstresses. This definitely is not a do-it-yourself product design.
As far as sending people copies of the patterns, I won't do that, for several reasons. One, the work involved in tracing all the pattern pieces is so much that I would have to charge a lot of money. Second, and more important to my interests, this is a proprietary product that I don't want people making bootleg copies of. I paid for the patterns and legal rights, and if copies get out in public, anyone could make and sell the tent without my knowledge or permission using pirated patterns, and in all likelihood these would be inferior copies that would damage Rivendell's reputation and possibly destroy my business. So, that's something I won't do, period.
My suggestion is to be patient and stay in touch with Eric or me. I can't absolutely promise the tent is going to happen, and I certainly never dreamed back in 1981 that it would take this long, but the ducks are lining up now. Eric already has the packs in production, and I'm working on the tent, which probably will stay with me, as Eric already has his hands full. One by one, I've been removing the stumbling blocks over the years, and it's getting close now -- certainly much closer than it was even 5 years ago.
I've provided a lot of information here, and I hope this gives you some things to think about in terms of what you may want to do.