Well, take the example of Softmaker, for instance. They make Textmaker and Planmaker, two excellent closed-source, cross-platform programs. Versions for Wince were available as well as for the Zaurus platform (admittedly they stopped working for the Z after it was abandoned by Sharp). I find it hard to imagine they'd have a hard time porting their stuff to the Itablet, especially as their software is as UI-agnostic as possible.

Edit: I tried -- foolishly -- to type a message on my Itablet again. And as usual, it got completely mangled. This is really getting beyond bad; no more Nokia tablets for me, ever again...