Note: smspillaz' comment in the IRC log is flat out wrong. Of course compiz supports two screens with different resolutions. The issue with multi-screen and compiz usually only is two different graphics cards. If you e.g. have ATI + Nvidia, you need two different libGL.so loaded in one process, which isn't possible.
It might be worthwhile to write a short test program that just opens an X connection, gets the root window for the respective screen and queries its geometry.
Note: smspillaz' comment in the IRC log is flat out wrong. Of course compiz supports two screens with different resolutions. The issue with multi-screen and compiz usually only is two different graphics cards. If you e.g. have ATI + Nvidia, you need two different libGL.so loaded in one process, which isn't possible.
It might be worthwhile to write a short test program that just opens an X connection, gets the root window for the respective screen and queries its geometry.