I'm in, if we can make a slight adjustment.
Instead of going through all the bother and expense and giving-out-mailing-addresses-ness of actually mailng CDs, why don't we just set up some happy FTP space somewhere and have exchangers upload MP3s to it for exchange? If you wanted to do groups of 5, that would be fine, too.
Anyone with the free RealPlayer and a CD-ROM can change music CDs into MP3s. Then, if they like the MP3s and want an audio CD, they can burn them onto their own CDs or minidiscs or whatever medium they like.
We can still keep the group-of-5 format, or do it however you want. We'd just need to find some FTP space. However, my CD-writer doesn't work and I don't give out my name or address on principle, so if you keep it the way it is you're missing out on all my wonderful music collection that no one but me can usually tolerate.
"Old" is the old new.