Thanks -- I'll check out the Elektrons and MPC. I've never worked with a hardware drum machine and hadn't considered one for this purpose... but if one of them has a fast workflow, per-step probability, good onboard sounds/effects, and overall is more fun than putting together drums in a DAW, it could work. I like modular's happy accidents, but maybe that approach isn't necessary.
FWIW, I already own the Rample, Pam's, the dual VCA and Noise Tools, which together would shave a good amount off the cost of the modular route.