Another vote for the Mamiya 645's with film inserts. whether you have the Super/TL or the earlier 645 versions without interchangeable backs, the reloadable inserts are the fastest going. If you had 3 or 4 preloaded inserts, you could reload very, very quickly. They are also fairly inexpensive; the going price seems to be about $40. The Hasselblad (and I've been using one for a while now) are a pain, even if you pre-loaded the film inserts. They're just not as quick as the Mamiya 645's.