This somehow passed under my radar.
YM-64 is a YM music player for the Commodore 64. It takes YM files and converts them either to a program or a SID file.
The problem I see at this moment is that I think the source code or tools to make this conversion are not available (yet?), however, you can get your ears wet with thousands of YM files already converted to SID or PRG form. I am just thinking there’s a bunch of cool cross-platform possibilities here, since the sound is not 100% exact, you could make new types of sounds in the C64 I believe. Also, YM/AY artists can compose for the C64 :D

You can mess around and change waveforms the emulator uses on the fly, also filter the sound. It’s kinda fun :P

Here’s the link to the player.