Anything in the Lenny catalogue, which is in the "armel" list runs in EasyDebian on the N900. These don't "need" to be ported to get them to work. To run in Maemo, software needs often needs a UI tweak (rewrite!). A proper Ubuntu mobile device would be interesting indeed. I wonder how open eiher the drivers or UI would be? The bits already are,, thankfully. Perhaps this could be N900 mk.2 ?