Rackmountable/Footswitchable....
Sansamp RPM
A little pricey though. For a pedal that you may compare and contrast to the Fulltone Bassdrive....you might checkout a Sansamp Bass Driver DI or one of it's offspring. Can double as a great DI for the FOH guys. I had the Bass Driver DI programmable. Has three channels that you can dial in a good clean tone a boost tone and a good grit tone or any combination there of. I loved that pedal and may find myself in possession of one again in the future.
The Sansamp VT Bass also gets a lot of love in these forums because of it's mid capabilities. I've never determined if it has a DI on it. Might be something else you want to check out.
EDIT: I have no experience with the Fulltone; but just wanted to throw these out there.