I've been wondering this for awhile now. I have the giveaway 5-1 Classics disc that came packed into almost all Sega CD units (this one is from the X-Eye). Anyhow, it has a version of Golden Axe that has its soundtrack in standard CD audio format. I came across Megadriver's site (http://www.megadriver.com.br/sitev2.cgi?disco) through sega-16.com (thanks Melf!) and Nino has remade the entire soundtrack with a metal edge! It seems like it would be a simple process, since Sega CDs use standard CD formatting. Copy the first track, convert/append the mp3s in the correct order and play!
I'm not familiar with the tools out there for this operation, anyone care to make a quick tutorial?