How hard would it be to develop an open hardware platform to deliver something similar to an OP-1? Do any such projects exist?
My favourite is the Chlorophyll box, which just kicks so much ass:
Or, maybe what you want is Anaologue Pocket?
https://www.analogue.co/pocket/
Dunno if its shipping yet though..
Maybe Axoloti is the answer. Its a very nice bit of hardware, I should use mine for things more often...