I think this could be what I've been looking for, to pair with the SP 505. It has what you would expect from an Akai controller, but with the ability to sample (no sequencer, but that's not what I'm looking for) and the major selling point for me; MUTE GROUPS!
I could get rid of the MPD26 and MS-1 and still work in the same way. Although I think the MS-1's with me for life.
Baked and GASing for an MPX16
Edit: Should have posted this elsewhere
MPD26>MS1, SP505 and things with strings (4 and 6).