I'm not sure if this fits the bill, since I'm not too familiar with what's played on amiestreet/audiolunchbox. (I meant to sign up for amiestreet but the site was too busy last time I checked a couple of weeks ago). It's a new service currently in beta and will be linked with a portable device sometime in this year.
CNET's Jasmine France (MP3 Insider) reviews it:
Does anyone know of any internet radio station that just plays music that can be found from places like amiestreet and audiolunchbox? Can last.fm or pandora be set to only play this type of music?