OK, back to Linux.
I have sorted out the right X server config.
Now, I am able to run Celestia through the 3 heads, which gives a resolution of 4480x1080 pixels (virtual viewport 4480x1024).
The picture shows 3 simultaneous, real time points of view of the Saturnian system - Titan on the left, Enceladus on the right - (sorry for the crappy shot, I am a noob regarding photography).
This is running with 8x full-screen anti-aliasing and 16x anisotropic filtering.
To ElChristou:
Well, 4480x1080 should be ok, right?
I would advise you to have some thorough read through the forums at widescreengaming and avsforums to understand what it is about.
There is really good read there, with return on experience from guys who run the latest stuff.
The screen is some 1.20 metre away and it is run with the highest settings regarding FSAA and AF. Picture's smooth as a baby's bottom, really.
To Fightspit:
And what about the horsepower to feed such high resolution with very high levels of FSAA and AF? Quad 8800 GTX SLI? How do you feed this 30" Dell display at decent framerates?
To bh:
I have a small collection of guitars (a dozen) and I like to have them hanging around

Intel core i7 3770 Ivy Bridge @ 4.4 GHz -16 GB ram - 128 GB SSD cache - AMD Radeon 7970 3 GB o'clocked - Windows 7 64 Ultimate / Linux Kubuntu