I did quite a lot of on line searching before I found my TM, and have a number of years experience with pop up trailers as well, so here's my 2 cents.
1) If it is the standard 2720 model, not SL or SD, the table becomes the base for the convertible bed, so it is custom cut to fit into the gap between the left and right seats, a store bought folding table wouldn't work if you wanted to utilize that bed. I believe some without tables have cut a piece of plywood to do the job, but that's 1 more thing to carry. The hardware for the tables can be found pretty easily and a carpenter could make one, but you'd need pretty specific plans for it to collapse and store like the factory model.
2) 2 batteries isn't a problem, I have 2-6 volts on mine, the solar links will help answer the rest of the question.
3) You don't say where in the US you are and prices can fluctuate a lot depending on location. I've found some steals using a craigslist search engine called search tempest
http://www.searchtempest.com/results...sk=&subcat=rvs
and oodle
http://rvs.oodle.com/trailmanor/for-...or+2720&inbs=1
but they are usually in less populated areas, the few that pop up in CA are usually at a premium. After a quick search I found a 03 in NM for 10.5, an 04 in Ca. and an 05 in IL for 9.9 and an 05 in CO for 15K, so prices can be all over the place, but I would say that 10.5 is a little on the high end, especially without the table, in this economy and time of year, unless there are already a number of upgrades or options, like 15" tires, 2" lift, wheel well mod, hanging cabinets, stereo etc. I agree that NADA tends to be on the low side though. I would guess a 3 - 5 year old one would be in the high teens, there seems to be a pretty big price drop as they approach 10 years old.
4) As for quality, it shouldn't be of any more concern than with any other camping trailer, most of it is comprised of standard rv parts, what sets TMs apart is the lift mechanisms, floors and walls. Like anything else, if a thorough inspection is done before buying and it's taken care of properly I wouldn't worry about it, you'll see very few issues on this site concerning those parts. Mine is a 98, was stored in a garage and I've had no TM quality issues, a huge step up from a tent trailer, especially in wind.