I did have the 12" combo and ext cab at one time but i couldn't really hear it on stage too well but it sounded great out front and sat really well in the mix. I was using my Geddy Jazz CIJ at that time. I always fancied the 212 cab that tilts back if needed. Such a great idea. The MB amps have a really nice warm tone to them too.
Does the Rithmic offer a decent tone form the pick ups. I think Jeff generally uses the bridge pick up so its hard to tell whether or not it would work in a more rock based band. Jeff also gets his frets levelled up by his luthier when he gets a new bass. I'll maybe look into it again. I love the look of it and as you hinted not many people can play like Mr Berlin.
Dave