If they don't want to alienate existing developers, a logical choice would be official Qt support for Android.
Meego could also be tweaked to run Android, as it is already being done by others, see for example http://www.aavamobile.com/
They could run Myriad's Alien Dalvik engine. I also agree that official QT support for android would be great as well. I think 2 open source mobile OS's rising at the top of the mobile market would be a great thing for wold. I think Apple will provide enough contrast with their closed iOS platform to balance things out.