I was going down the road of still using 2 controllers, but looking at 2 SAMD21 chips (or similar) on a single board instead of bolting on full uCs (though more or less the same as that). The approach there is mostly because I’m comfortable with Arduino and it’s easy for users to re-program, etc.
I’ve not done enough research to see what other chips might have multiple ports.
True - but was hoping to add more functionality and configurability, etc.
I think this may be similar to what @scanner_darkly and I had worked on awhile back and I got stalled on hardware, although maybe not as robust as what you describe.