I understand your question, but don't know the answer. However, there may be a work around.
I've collected MP3 music from the old free Napster file sharing days. I've also made mp3s from old albums and tapes. Many of my songs have improper tags.
To make things manageable, I made subfolders for different types of music (rock, rap, jazz, blues, et.). On my home computer, I organized all my music into the proper folder. Then I transferred all the subfolders to the Music folder on my Droid.
Then I downloaded mortplayer from the marketplace (it's free). It's the only music player (that I know of) that can recognize folders. I can tell it to play random songs from the "Rock" foler (or any other folder).
This isn't exactly creating playlists, but it's one step closer to it than complete randomness of 8 Gigs of music! Hope this helps.