I'd love to program for the N800, but there are two reasons why I currently don't:

1. I don't know GTK (yet)
2. I don't / won't have a development system

I don't have a computer at home, and my job will be ending soon, so my sole development platform will be going away. I'll have lots of free time soon, though, so I may take a look at on-device development (which I seem to recall seeing posted about somewhere) and learning GTK.