Thanks for all the great advice!
Now I've got some choices to think over. I hadn't considered a Birdy because I thought they were too expensive, but it does look like the Yellow sneaks in just under the $1000 ceiling.
It sounds like modifying a Downtube, because of all the standard parts, might be another good option.
Can anyone tell me what the approximate fold size is if the rear shock bolt is removed on the FS and the wheel pivoted under in the fold?
Any comments on the Dahon MU SL or Speed Pro. Both look to have longer reaches and fast tires but I've seen several comments about the proprietary parts making them difficult to repair/modify.
Thanks.