I got a demo device from TriPlay to show off Musix running on the blackberry device using the blackberry native LWUIT port.
The UI worked pretty smoothly and was relatively easy to port, most of the work in porting was related to networking on the RIM devices which is really complicated.
While the menus/UI is in Hebrew the application shows off background downloading with decryption on the fly of DRM protected music. It also shows off album purchase (e.g. the Pixies album in the video).