Is there some way to move Windows between separate X screens in Ubuntu 12.04? With 3 monitors on 2 GPUs, using Twinview is not an option. Xinerama allows me to drag windows between all monitors, but it also means that I lose all hardware acceleration.

I don't expect to be able to drag windows between the screens and have them occupy two monitors simultaneously, but there must be some way to transfer a program while it is running. At the moment, I don't even know how to select which monitor it will use when launched.

Any pointers?