At first, I want to say "Thank you for your work, marmistrz!"
Then, may be it is stupid, but have you tried Fennec on N900?

No, I didn't try, but Fennec won't problably work (firefox isn't qtwebkit)

QtWebkit viewer is the thing which will most probably work (offline apps, non-faceless and not using ares.js work alright)

I created a thread here: http://qt-project.org/forums/viewthread/18821 so that maybe someone helps me with making the viewer appropriate for Mojo apps. If someone knows a solution for one of the problems, please let me know!