I think the best way to make sure that your app works on MeeGo is to use plain Qt. As stated in the previous comments.

If you have checked MeeGo architecture diagram there is one UX layer e.g. for handsets and another one for netbooks. If your application depends on one e.g. handheld UX layer it isn't guaranteed that it works on netbook.

The common nominator for Maemo and MeeGo is Qt. As you may have noticed, Qt can use a custom style for example style for maemo5 or in the future MeeGo style (i guess) which provides platform specific look and feel for your Qt application. This way you can get good portability between difference devices, but you don't get the eye-candy that UX (transitions, custom components) provides.