Just to let you know about KORG RPPR.

The patterns are not like arranger keyboards.
They won't change chord. So you will have to create a pattern for each chord.
The patterns are not multitimberal. One pattern for each part. So you will also need a pattern for each track.
One pattern can be mapped to one key on keyboard. The mapped key can't be used to play regular sounds.

So. If you have 4 variations of a 5 track pattern, and 4 chord changes. You will need 80 patterns. And you will need 80 keys on the keyboard. If you map all keys, you can't play a sound live. Because every key is playing a pattern.