So, I just got an used N900 (but in very good condition) for about 55 euros. Now I have to reinstall every app (including catalogs and all) to customize it the way I want (it may take a while).
I ditched the idea of using the backup from backupmenu as I would like to have a fresh install with all the configurations.
I will try to open the old N900 and clean it just to have a backup (I hope I won't break anything and that I will be able to assemble it again).