Yes, sulu, but would you call desktop UI on the N900 "usable"?

Maemo uses text size from 40 upwards. Buttons 60 pixels high (I do not remember the exact details but I do not think I am too far off). As opposed to text size somewhere between 8 and 12 on a normal desktop. That is what I meant by "designing a UI specific for small screens" in my later edit.

I tried a few desktop apps - both in Easy Debian and ones I compiled myself - and I would not call them exactly usable. You could use them in an emergency but not every day.