3D MergedFB radeon support for screens > 2048x2048 ?

[Mitch]

Hi,

Screen resolutions of 1280x1024 are pretty much standard these days and 
i note from the radeon man page that 3D is disabled for Mergedfb when 
using two screens with a combined resolution of more than 2048x2048.

So what's the solution if you want to use dual screens (bringing the 
resolution upto 2560x2048) with 3D support ? I'm assuming there is a 
technical reason why it's not supported at this res ? Is the limitation 
not there in the propiterary ATI drivers (before i start downloading 56M 
of driver) ? What about using Xinerama ? Any other ideas apart from 
forcing my resolution to 1024x1024 for each screen ?

Thanks
M