Just as an FYI, I also saw my battery level dropping rapidly throughout the day today, after flashing my ROM. However, I'm trying to drain the battery to charge from scratch, and it just won't die!
I've had it on for the last 2 hours (just to the home screen), and my battery level has dropped about 10%. I'm still sitting at 7% right now. Gonna see if by going through a complete cycle, it will improve anything.
Clint