I've packaged this into a standalone tool to make it easier to convert MIDI arrangements into native Blob Opera format (see readme for why you might do this instead of just using MIDI signals)
I've made a number of updates to the standalone tool. I realize it's still extremely hacky to use but I'm pretty happy with it as a kind of holiday art project. Version 1.0.4 fixes a bunch of timing issues from my original script, so if you tried this out before and got less than optimal results I'd be very curious if this resolves any issues.