But... I tried it out with the combo tonight! The band is normally guitar, vibes, drums, and bass (me). I told them that I was messing around with the cello, so they encouraged me to bring it. And the drummer's son is learning bass and progressing nicely, so he played with us too.
It's kind of an experimental band anyway. We play whatever the guitarist writes -- modern jazz compositions, plus transcriptions of new material, etc. It's kind of a "workshop," for instance if someone wants to work on some particular thing, the band will oblige. So it's a great chance to try out something new.