Depends on your priorities. I love both my 2 wheel and 3 wheel recumbents, for different reasons. All things being equal, I find a 2 wheel recumbent much faster, but a 3 wheel recumbent much more relaxing (ie no danger of tipping over, even on steep hills at low speed). There is more discussion of this here: http://ergocycle.ca/index.php?main_p...id=3&chapter=1

It depends. It does take bit of getting used to, and it is harder to get used to as the bottom bracket gets higher, but in either case, it is not that hard to get used to.

Trikes are wide, but because they are totally stable, it is much easier to track in a perfectly straightline- bikes generally tend to need a bit more room- check the tracks that wet bike tires leave- there is often a bit of weaving. Bikes are narrow on the ground and wide up high, trikes are the reverse- psychologically this does seem to effect drivers, who give me MUCH more space on a trike than a two wheeled bike (recumbent or DF). In many ways I prefer a trike for road riding, but it is important to ride in a vehicular manner.

It depends on the model. I would say most recumbents probably have booms that extend and retract, but some have fixed booms with seats that move. Many recumbents have a single frame size that can be adapted by moving the seat and/or the boom, others have a variety of frame sizes, and other adjustments to fine-tune the fit. Getting the right leg extension is every bit as important.

Again, it depends. A number of people with back problems do report feeling better after a nice long ride on their recumbents, suspended or not. I think that a test ride is the best way to sort this out. Personally, I have had two trikes that are unsuspended, both have mesh seats, which does provide some passive "suspension". I have had two highracers that are unsuspended, these have been fine for my purposes, but big bumps can rattle the teeth a bit. One thing to keep in mind is that good suspension is difficult to engineer, poor suspension is very easy. Without a test ride, it is often hard for laypeople to tell which is which.

It depends. If you search on bentrideronline.com, you will find that a number of people with folding trikes can fit them inside smaller vehicles than you have. For my two-wheeled recumbents I now have a Thule fork mounting tray for my roof rack.

Recumbents are still definitely a niche market, where we are looking at small batch production runs. This is expensive, but on the other hand, there is generally a high level of craftmanship and commitment on the part of manufacturers. If it is a tandem that you are looking for, and you are leaning towards trikes, I think that this is probably your best bet, but it is still way out of your price range:
http://www.tridenttrikes.com/chameleon.htm

This is manufactured by TW-Bents. I am biased in their favour, as I am the Canadian importer/ dealer for TW-Bents- I think you will have trouble beating the quality at that price. Actionbent is an American importer/reseller. Personally, I have emailed them to ask a couple of questions, and all I received were marginally coherent, rude, hostile rants which failed to answer my questions. Thinking we got off on the wrong foot, I tried to re-phrase my questions politely, and again, I received a marginally coherent, rude, belligerent, totally uninformative reply. You might want to try Boomer Bents and Bikes (http://www.boomerbentsandbikes.com/i...hp/trikes.html), they carry many of the same products, but have a much better history of customer service.