The Plonky script on the Norns can split the Grid in two halves for a total of eight sequences , keyboards and/or arpeggiators across four pages (so two play areas per page). I can also play Supercollider synths (including various Mutable Instruments clones with a bit of clever patching), multisamples and/or MIDI out per half-grid.
There’s probably other similar Norns scripts that can do something similar that I can’t bring to mind right now.
The Polyend Play looks somewhat like that concept taken to another level altogether with far more complex playing routines.