Thank you for sharing your work! I am myself on holidays as well, I did not bring my APC Mini, I will test when I get home. It feels like a really good step forward. I think this kind of feature should be enabled more easily by VCV through its API, e.g. a plugin could specify in its manifest which controllers (using device ids for example) are compatible. Along the same line there could be a widget to select both MIDI in and out, you rarely need to only send feedback or only receive input.
I do have my Akai Fire with me though, for which I am working on a similar module (as I explained here)
Sadly the Fire makes heavy use of SysEx for most of its interface, which is not working in Rack v1. The Fire also integrates a screen, shift and alt keys, leds and knobs ; I felt it makes sense to write a module dedicated to it, though as I said in the link above the programming work could be made much easier using scripting languages.
Anyway, I’m happy to see other modules do the same and I wish we can collaborate where useful to both of us! Thanks.