I've got a set of Moog Taurus II interaced to a Moog Source. During the mid-80's when I first bought them both, the set-up was great! It's rather limited now by today's standards, but the Moog bass sounds are still to die for.
I also have a set of Roland PK-5 pedals MIDI-ed to a Roland D-110 rack module. That's much more in keeping with todays sounds but the D-110 isn't the best synth either. I set it all up on the cheap about three years ago, as an experiment to see if it was worth progressing. Lack of cash has prevented that path from happening. But the PK-5 are very versatile from the point of view of adjusting settings for a few parameters with your feet as you play. I'd recommend them - just think very carefully about the synth you interface them with.
Of course, there are still the original Moog Taurus pedals but they're not MIDI either, they'll cost you a fortune to buy (if you can find a set in decent condition) and they're all getting a little old and fragile now. Not something I would drag around to gigs these days, for their own welll-being!