recently a minigsf set was made for Gunstar Super Heroes (by unknownfile on the hcs64 forums). It may not be the final version (it seems to be missing "SORROW"), but more important than any of the things it's missing is what was found in it: seven tunes from classic Sega games, none of which I've ever heard during the game proper.
http://www.fileden.com/files/2007/9/1/1 ... ighter.mp3Galaxy Force II
http://www.fileden.com/files/2007/9/1/1 ... gpoint.mp3Thunder Blade
http://www.fileden.com/files/2007/9/1/1 ... akeoff.mp3After Burner
http://www.fileden.com/files/2007/9/1/1 ... dbeast.mp3Altered Beast
http://www.fileden.com/files/2007/9/1/1 ... atboss.mp3E-SWAT (the Genesis one)
http://www.fileden.com/files/2007/9/1/1 ... erness.mp3Golden Axe
http://www.fileden.com/files/2007/9/1/1 ... galaxy.mp3Galaxy Force II
(if you're wondering what 19 is, it's "ORDEAL". I'm not sure why it's in the middle of those...)
I noticed a thread on 2ch (which I wish I had found a few days ago, when I only knew about Alone Fighter and Final Takeoff and had to find the rest) which listed these songs as "unused" and seemed to indicate similar surprise at their existence.
I checked old previews and noticed they mentioned music from these games being in GSH. I guess that had just left my mind after I assumed they were scrapped along with the Altered Beast segment and whatever other Sega references didn't make it.
But now I'm wondering, what if things other than the music weren't scrapped? What if they are still lurking around somewhere in the ROM, waiting for an intrepid hacker....?