I think this is indeed a very bad news. I was under impression nothing could break the Qt cross platform as up until now you were able to create an application and run it in Linux and Windows and it always looked proper on the host os. Hack I even took a windows small app and run it on wm 6.1 and it looked as it should. Just like a native application.
I really cannot understand why when qt gets compiled to maemo the UI doesn't bind to an underline maemo library of widgets, same goes for symbian or linux or something else and look the same from a coding perspective the same. And use in addition styles to skin as desired.
If multi touching doesn't work on that platform then simply it will be disabled. If touch screen is not available than disable that too.