Nice to see that somebody has the same questions as I have
In addition to the above questions I'm also very interested if anybody has experiences with dual-monitor setup with GMA HD?
The main problem is - what is the maximum supported resolution with hardware-accelerated OpenGL? Currently I have a Radeon R300 and it has the limit of 2560x2560px with hardware acceleration, so using dualhead configuration with desktop width about 3000px forces me to disable OpenGL effects for the desktop (KWin).
I asked the same question on intel-gfx mailing list but no one responded, so maybe here I can find somebody using this integrated graphics with dualhead setup...