I do think you need OpenCL to work with the GPU of the ATI card...
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/GPU_Rendering

Yes, you will need OpenCL, but it more complicated than this: for some reason, OpenCL is deactivated in Blender on Linux. There is no way to find out why, there are threads with like 18237823 posts where I could not gather what the status now is.

Though I suspect that could also cause trouble by trying to use the GPU
for the "work view" too....
It could be that it already, all by it self figure out that it wants to
use your ATI card?

If you open a xterm in the X2Go session and crank this:
"blender -d -f 1 -b" does it render a cube to your /tmp/ ?

Yes, just tried that. That does render a cube.

Btw. how would X2Go shadowing :0 work for you?

I'm not familiar with shadowing or what that means. Do you mean running x2godesktopsharing on the physical display on the server and then connecting to it via X2goclient?

I was not even aware that x2godesktopsharing worked already, just tried that out. Is there a way to enable desktop sharing for every session automatically?

Just skimmed through the doc... looking forward to see the videos.

I will do these in the next days. I thought it might be cool to be able to show somebody what the whole process looks like, visually demonstrate what X2go can do.

As they say in German: Ein Bild sagt mehr als tausend Worte. A Picture is speaks more than a thousand words. But well, video has more than a thousand words per frame, so 24 fps, that would be more than 24k words per second ;-)

I guess applying cold math to a artistic proverb might not work.

As for IRC... make sure you are on a freenode server... then enter #x2go rom
What IRC client are you using?
You should always see a bunch of other users.... but quite often it can
be a very quiet place...

I'm using the one that gets bundled with KDE, don't know how it is called.
I will log in and stay online 24/7, I think that should do the trick.

Thanks,

Markus