lol, loving how times change, did few searches on 'N900 battery' in few options to help google, bing first search returns someone actually selling and listing compatibles... times are a changing, try battery if one of your friends have:
Nokia 5230 XM, 5800 XM, N900, X6

Cold flashing with a fresh battery from some of those might help, use goo... **** it, use bing, lol