I'm not sure if you'd be able to modify it, but I have a suggestion for the way the OS handles AVRCP (bluetooth controls) commands. First, let me give you the situation, then my suggestion:
I recently purchased a bluetooth stereo headset. It works beautifully, except for the controls. I use Pandora almost exclusively for my music (99% of the time), and 80% of my time listening to music is at work. In my work environment, I have to constantly pause the music for various reasons (meetings, people stopping by my desk, me stopping at others' desks, etc.).
When I push the Play/Pause button, it almost always (about 95% of the time I estimate) it sends the command to the stock music player, which then starts playing a random song. This occurs even if I have Pandora in the foreground and am looking at the screen. The same thing occurs with the ff/rew buttons as well.
I found an app called Headset Button Fix (Headset Button Fix - Android app on AppBrain) that was written for the HTC Hero, but worked with my D2, for the most part. What this app did was redirect the functions to whatever the last player was that was being used. My two gripes with the app were that 1) You had to start the app, then click a button to enable it, and 2) It did not work 100% of the time, but probably about 80-90%, which is still a big improvement.
Now, the suggestion:
Would it be possible to incorporate a feature like the app did to redirect AVRCP commands to whatever the latest player was?
This seems to be a big gripe with a lot of people from what I've found online, with no real recourse. It may also bring a few more users to your ROM if it's incorporated as a lot more people are starting to use bluetooth for music, and this is an issue across the board, with all devices and ROMs.
Thank you for your time.