in general, stay the hell out of X and stick to the command-line. That, all by itself, will save you a ton of time. Also, no playing/streaming of media (that's not what you got BT for in the first place, right?).
There are power-management tools available that might be able to help you, but i think there is a more fundamental issue here. BT is designed for pen-tests, vulnerability assessments, etc. and I have yet to be able to accomplish any of those in half an hour... (trust me, if I could I would). So, it seems that you may be wagging the wrong dog here, neh?