The cake, it was a lie

Phonon allows us to "upgrade" and change multimedia systems in the background without the developers even having to rebuild their apps, let alone port. We basically port it one, or add support for a new backend, and it's transparantly available for apps that have been compiled even before that mutimedia system or backend became available. That's the benefit of having pluggable backends to stable interfaces.

There are no plans to move to QtMobility and/or QtMultiMediaKit, that I'm aware of. And looking at QtMobility's source, that's a good thing. Hack, the 1.2 release didn't even build out of the box for me...