acronym.esq wrote : "My current total pack weight is about 28 lbs (very near the limits of many UL packs). Dropping my current pack and replacing it with a UL pack would bring my total pack weight down about 2 lbs."
I would work on the contents of the pack first, then replace the pack when you have the load light enough for a UL pack. If your load is 28 pounds, you may have some work to do before an UL pack is really workable. I guess the question is, 28 pounds with how many day's supplies?
Keep in mind that most UL folk talk in terms of base loads (sans water/food/fuel), where pack manufacturers are listing *maximum* recommended loads-- the whole enchilada. A *comfortable* load is probably a good percentage under the recommended maximum.
*Generally*, if a pack design has a sleeping pad as part of the pack system, it is one of the lighter cottage industry rigs and best with lighter base loads. I don't know of any factory made packs that are deliberately designed to incorporate a sleeping pad. Some can be adapted.
If you are using an internal hydration bladder, that will add to the picture.
As others have said, you can arrange the items in your pack so that you aren't being skewered by the contents. I use a Thermarest Prolite short pad and pack it folded and placed against my back to add padding. My sleeping bag goes in the bottom, with tent parts on top (if I'm using a tent) pad against my back, clothes next, and then food and kitchen kit outboard. My kitchen kit is probably the lumpiest/hardest of the contents. Tent poles go down the side. Survival and hygiene items are in the outside pocket. I'm using a pack with compression features, so I can suck the whole works down tight and stable.
The sleeping pad-as-cylinder trick can work great-- best with closed cell foam pads and simple pack designs, IMHO. I put a trash compactor bag inside the pad/cylinder and start stuffin': sleeping bag, tent parts, clothes, kitchen kit, food.