Steve,
We bought a 7-gear Giant Halfway last summer. It's a beautiful,
well-designed bike, folds up very easily and rides very comfortably.
The cost was $550 including a carrying bag.

Mfg: Giant - check under specialty bike
http://www.giant-bicycles.com/us/page.asp
Model: Halfway (halfway between a street and dirt bike). 20", 7
speed
Reviews:
http://www.pestridge.go-plus.net/transport/giant.html
http://philip.greenspun.com/flying/shopping

It's a bit more heavy than the 8-speed Dahon Helios P8 which was
also under consideration (28lbs vs. 23lbs). The several months backlog
on Dahon bikes and some of the bad reports on this brand reliability
and mfg support were the reasons for the Giant Halfway purchase.

We have not tried to fit the bike inside our Cardinal FG but would
not expect any problems. Originally we had planned to get another
Giant but I may end up getting the Helios P8 to save some weight.