OK, I've been really lethargic about this, I know. But it looks as if things are finally moving again. Managing to successfully rip the music from an old Archimedes game which I'd been coveting for ages helped a lot with my motivation! Jason Page documentation has once again moved to the top of my list.
As it stands, I'd estimate it's about two-thirds done (and about one-third of that happened in the last few days). The core stuff is all in, but there's a load of appendices to write and lookup tables to calculate. The good news is that I haven't found any more mistakes in my conversions (although I have learned a lot more about a certain feature I decided not to implement, which was satisfying, albeit in a way which helped me make a more informed decision about why I shouldn't implement it).
If all goes to schedule (trust me - it won't), I should have something to show by the end of the week. Warning: the documentation is set to be huge!
Asle: Are you waiting on the documentation so you can write your own converter? If so, I really wouldn't bother - it's a lot of effort, and I've done it all for you.
If there's demand, and now that it's working again, I could upload the up-to-date zip file of all the tunes to the FTP.