The Roland VariOS has a nice software synth, the VariOS-8, based on the legendary Jupiter-8. Problem is that you always need a computer to modify/create sounds. But with the Behringer BCR-2000 and this template you can use your VariOS-8 as a standalone synth.
Download the files from this page:
The download consists of: BCR-2000 File, Manual and two designs for upper and lower part of the Behringer BCR-2000.