Basically, you submit a song for a compilation. edited It costs $675 per song (thanks for the heads-up ericcoleman). Whether this is worth it to you to get beyond live appearances and Dr. D. is up to you. Can't hurt to make inquiries. I assume standard union rates apply if the song actually gets played on the air.
The Acoustic Rainbow CDs (and other compilations put out by the company) are more folk/old-timey than demented, but you never know what might interest them. My guess would be along the lines of Riverfolk and Carla Ulbrich. Worth a look.
Crossposted to barondave and marscondementia.