Pandora, Personal Media, and Integration

I have two wonderful sources of music while I'm on the computer and working: Pandora and my personal MP3 collection. Now, often when I am listening to Pandora, I think to myself "I'm in the mood for a few songs from Tangible (of 8bit People)" and sometimes, when listening to my MP3s of Harvey Danger's latest release, I get in the mood for some songs from my personal Ventures radio station on Pandora. Makes me really wish there was someway I could keep a list of Media Resources registered on my computer, with a player that can be set to randomly request tracks from each of them, randomly. Request a random track to be played from Pandora, then one from my own collection, then play a song from one of my favorite Shoutcast stations, a few from Pandora and my harddrive again, then maybe something from my computer's Radio Tuner. Anything like this around? Does anyone know where to look into this sort of thing, existing or in some form that could evolve to this?