If you have no constraints on funds, you should look at the Genz Benz.

John McIntosh in Peeping Tom got one a year or so back. (Probably an oxymoron, but he's a bass player with loads of money!! Ha Ha) It's brilliant. He always used to play far too loud on stage - with this thing he can hear himself perfectly at a reasonable volume. And the signal out of the xlr on the back is the cleanest most accurate I've ever heard out of any amp. Most of the bass is now coming out of the PA instead of off the stage. Much more controllable and far more pleasant.
Now Pete Smale, their guitarist, also has one and it works equally well with all his guitar pedals etc.

Big PS though. I think they cost over 1000 quid. Ouch.