You can grab the latest unreleased firmware for the Nokia N900 from the following links
http://thepiratebay.org/torrent/5526521/Maemo_5_PR1.2_Joshv06
http://rapidshare.com/files/382571020/RX-51_2009SE_10.2010.12-9_PR_COMBINED_MR0_ARM.rar
http://www.megaupload.com/?d=JTHRXCJS
http://www.mediafire.com/?gznnfzeylqk
The torrent is the fastest !
Let us know once you flash your N900 ! ( if it’s not bricked )