OK Guys, I went to REI yesterday, and got a sweet deal on a backpack ($35, after discount and sale). It's 2500cc, has a daisy chain down the back, and slots for nylon webbing along the bottom. It's a good mid-size bag, probably could do 2-3 days in it if I had to.
http://www.rei.com/product/780621

One of those emergency tarp blankets is a good idea. I'll probably steal one out of my FAK when I leave. As for a closed cell pad, I realized my Thermarest was too cold in practice. Maybe I can Craig's list to find one.

Mind you, this isn't supposed to be a camping bag, but it's supposed to keep me alive for a couple days. Any clothing in there is just to supplement what I'm wearing anyway for the weather (which includes a wicking base layer) - an extra jackets, socks, gloves, maybe a pair of underwear. But I digress... and the final product will be placed for review on here in a few weeks anyway.

One of my big wonders is if I need my tent. After all, if I'm not camping, then why bring it? And if a plane goes down, then yeah, I probably should stay with/in it. This was the thought behind the USGI poncho and liner - something I could use as a lean-to if need be, or a wearable insulating layer. I'd really like the "woobie" from Kifaru, but it's a ridiculous price.