OK, we have quite a few DRM-free games here, there are many soundtracks for them, but unfortunately in lossy MP3 format. Wish I could get lossless ones, even iff I had to pay for them ...

In many cases it doesn't exist. Because most of these games are old, the original materials (such as audio recordings) that went into making them have been lost in the mists of time. Unless an actual OST CD was published for a game, it's likely that the only version of the music that still exists is the one actually used within the game.

Of course, some games used redbook audio originally, and some of the GOG versions still do, although I think they've begun to phase that out in favor of .ogg files. I know Heroes of Might and Magic 2 used redbook audio in the original GOG release, but has since been changed to .ogg. Redneck Rampage also used redbook, but I don't know if that's been changed. Anyway, if you have a GOG game that does use redbook, you'll find a CD image in the form of a pair of BIN/CUE files in the game folder (although their extensions have been changed to .inst and .gog). You can just copy these files, rename them to .bin and .cue, mount them as a CD in the virtual drive software of your choice, and rip the music losslessly from there.

Ya, it would be awesome to get the soundtracks on vinyl.

If only GOG went physical...
"A man can dream, though... a man can dream."