Hi,
the closest I've gotten to a psr module is my laptop & omb software.

It's a real pity manufacturer's don't seem to make them anymore ( except Solton, I think still has one?).

Roland made at leat 2 or 3 models back in the 90's, korg had one too that I know of (i5m ) and even technics had an early module, based on the kn2000 ( I think).
Only thing I can think of is that they musn't have been big sellers or we probably would hve seen more models around.

Personally I think they're a great idea.

best wishes
Rikki