...a hybrid dual manual instrument, looking something like the dual keyboard organs out there.
But -- the bottom keyboard would have a good quality hammer action for piano feel, and the top would have organ feel with waterfall keys. Horns, strings, synth sounds, etc. should be on board for use on top (but also with the ability to play on the bottom). Piano, EP, clav, etc., should be avilable for the bottom (but again, accessible on top if needed).
But -- the bottom keyboard would have a good quality hammer action for piano feel, and the top would have organ feel with waterfall keys. Horns, strings, synth sounds, etc. should be on board for use on top (but also with the ability to play on the bottom). Piano, EP, clav, etc., should be avilable for the bottom (but again, accessible on top if needed).