As you may have noticed I stopped working with Ubuntu and switched to Arch for N900. The main reasons are:
0. Chroot from Maemo works on Arch.
1. Active work of others with Arch.
2. Lack of interest from Ubuntu/Linaro people.
I'm going to try 13.04 but not sure about the future versions.
I encourage everyone to try Arch too, here is the thread:
http://talk.maemo.org/showthread.php?t=81892