Is there a way to convert your own cache to a package so it doesn't get removed? If you go to holiday or a summit and cache an entire town.. it's a waste to have Marble throw it away!
And where can I find those offline Berlin placemarks? I cannot wait til august.
As for QML porting you mentioned earlier, navit has a quick and dirty proof of concept optional QML interface, so I guess it just works on the N900.