Hello Bill! I am happy to see you around here, but very sorry that you have been held back in your plans. I hope that everything goes well and you are able to continue soon enough.
I realize that making a hammock based on available instructions is a cinch, and I have some MYOG experience. The reason I asked is that I live overseas and will have exactly 1 day in the Denver, Colorado area to do all my errands before beginning a 45-day CDT/CT yo-yo in Colorado. I could order cuben fiber, pick it up in Colorado, and make the hammock that same day, but I will also be stopping by REI, the pharmacy, health foods stores, and a half-dozen other places, in addition to dividing up my provisions for later resupply.
I have seen the questoutfitters page. Their cuben is 4'2'' wide, and I'm pretty sure I can do with that. I don't weigh much more than you -- 170 lb. -- so I would go with one layer. Plus, if what they say about cuben's tear strength is correct, this would be stronger than the parachute nylon used in The Travel Hammock, which I have.
I understand what you say about the forums here. Forums generally aren't the best places for storing accumulated knowledge, and the lack of a sophisticated search here means that you think, "ah, whatever, I'll just start a new thread instead of spending 2 hours sifting through all the threads with the word 'hammock' in them." So blogs or even wikis are the way to go.
4. Yeah, I can relate :) I've never used cuben before and have trouble ordering it from where I am, so I have the Creeping Condensation Concerns, too. However, the idea of having a hammock that blocks wind, is rain-proof from below and saves me the time of jerry-rigging my space blanket shield underneath is really attractive.
6. Yep, I'd imagine you'd want to avoid putting any holes in the construction. So I'd imagine you can put a large side pocket with a drawcord on the hammock, then have this convert into the hood of the poncho. It would hang 50'' down your back, reaching your lower thighs, and the rest of the hammock would drape around the front of you in two overlapping layers. The single back layer could have two clips opposite the hood (i.e. at thigh level) that allow it to be attached to the front layers. Is this what you've had in mind?
As for the tarp mode, you'd have to find some way of working around the fact that the hammock is drawn together at the ends. Untying the hammock to turn it into a tarp is really inconvenient, so what I envision is having four "corner" loops for the tarp right where the hammock begins to taper. This would allow the effective length of the tarp (perhaps 8 feet?) to be pitched tautly, and you'd just have to tie the hammock ends to something to keep them from flopping around. On each side of the hammock you could add, say, 2 more tie-outs (avoiding the hood/pocket) for better tarp pitching.