DefleMask author has included the huc6280 audio into his tracker app. I messed with it a bit and once you figure out how to edit the instruments and waveforms, then it becomes fairly familiar tracker territory. It has a macro function (in envelope form) for waveform updating, which is nice (ala Bloody Wolf and a few other rare PCE games). Doesn’t seem to emulate the ‘click’ for the offset waveform pointer though (maybe I’ll put in a request for it). You can find it here: http://www.delek.com.ar/forum/changelogs/changelog-6/
The native format is DWF, but VGM is now spec’d for 6280 so you can save it in that format too. Shouldn’t be too hard to write a VGM player for PCE. So far, I haven’t seen any support for DDA mode in the tracker yet (VGM format supports it though).