is there a 2560x1600 quakeworld wallpaper out there?

You want the Q logo in that resolution, or just a Qw theme?
Also welcome to the forum, enjoy your stay!

http://gfx.quakeworld.nu/details/61/ <-- try that conback as centered wallpaper on black background... should kinda work ...
otherwise ask the gfx-pro's, maybe they'll do something...

I can make one for U, if You still wish to get it.....

Please do, we're always interested in nice artwork!