1. What Peter said.
2. The Utah Trikes Rover x5 (WITHOUT THE 26" WHEEL) and with the 27 speed option would be a capable hill climber. While the Rover x5, 26" rear wheel, has a gear inch range of 24-72 GI, the same machine with 20" all around would have 16.5 - 88.3 GI.
I have the x5 with big wheel and I can tell you that 24 is too high for around here. There are slopes where I am in 1x1 and looking for something lower.
My retrofit, suggested by UT, was to mount the Lasco 152 mm crank set with 22/32/44t chain rings. It should produce 16.8 - 104 gi. Stay tuned. I am going to test it this weekend.
Meanwhile - for some Rover Bike Bling, check out the pix...
<http://s1222.photobucket.com/albums/dd500/trailbear/>