Jason,

amati makes a type VIIb that is about 3 feet long, it is 1:72 scale, and "Nature's Coast Hobbies" has it listed for $200us. if you build it so that it is a dynamic diver, you might be able to build it with a three channel radio and speed controller for under $500.

The kit is solid resin, so it would need to be hollowed out, or better yet, it could be used as a mold to make fiberglass reproductions...

I own the U-47 by robbe, and I can tell you right now, there is no way you can get it on the water for less than $900us, if you include the cost of a 4 channel radio, speed controller, and batteries. more if you modify it so it has a ballast tank.

web link for amait VIIb is:

[naturecoast.com]

if you want to try to R/C it, try this website:

[community-2.webtv.net]

I believe the amati is also reviewed here on uboat.net

hope this helps

Tim