Adding stuff like Pandora, Slacker, etc is not just a matter of writing the code.
It also requires having a contract with the companies involved. In the particular case of Pandora, one generally needs to have an agreement/contract and set of keys for each model of device that is supported. We currently hold the key pairs for the chumby and Insignia devices. We do not have keys for the dash, since Sony handled that.
I certainly have the code to support Pandora on dash - what I do not have is a dash key pair to make it work legally.
Technically, I could use a chumby device key pair, but that would be a violation of contract and we could lose Pandora for *all* chumby devices.
I didn't take Pandora away from dash owners - Sony did when they stopped supporting the dash.
The dash CP does support external music sources from USB, same as most other chumby devices, example and documentation here (note the files included are sized for 3.5" devices):
http://files.chumby.com/widgetexamples/ … lMusic.zip