Analogue-sequencer

>>it would be nice to have for example two rows of 16 note knobs
instead of one, which could be split if desired to cover any 4 tracks
instead of just two (or one even, as on the P3) at the same time. With
some indication somewhere of the 4 tracks that were being controlled.
.....And it wouldn't surprise me if someone comes back and says "the
P3 can do that already!"<<

the P3 can do that already. 
sort of. 
you need to be grabbing knobs, graham.... :-) 

& then don't use mixer mode.

I have experimented with a pseudo-maq setup where two rows of 16 knobs
are "live" into two (or more, actually) tracks. you could use
different configs but then the chase-light gets confusing....

d.