I done stick my nose in this here prototype area too often, but I thought I'd take a few minutes to check it out. Cool stuff!
I just wanted to post a standing offer for dumping any proto or rare carts anyone needs dumping. I currently have the ability to dump:
SNES
Sega Genesis
Nintendo 64
It's pretty exciting to think there are still games out there that no one has discovered yet!
EDITED FOR CLARITY: This means I can dump existing US carts into ROM format for computer use -- not the other way around (making carts out of ROMs).