I don't know how long it's been since I popped my head in this thread, but I thought I'd just mention the status of a2dp on my own tablet, currently:

As johnx mentioned before, after flashing to Diablo, there were some weird issues getting a2dp working, but I believe repairing my headphones and rebooting is what actually solved it.

I can currently play not only audio, but also video with mplayer flawlessly, encoded at very high quality. Here is an example of a video file that plays very nicely: http://www.ageofikon.info/N10-Haruhi.avi (Melancholy of Haruhi Suzumia AMV).

Just thought I would let everyone know, in case there is any question of how well you should be expecting a2dp to work.

Note that as of this moment, I have gotten lardman's SBC DSP task to play audio very well, but I still have to use the software encoder for video to work well (it basically just freezes the video stream and the audio stream is very choppy using the 1.0 release of the DSP task). Hopefully when he releases the new version this will be improved. Gogo lardman, you are my hero!