GURPS Space Empires? It could be a pretty simple set of details to add to GURPS Space, except the work of developing the alien species details.
There were already fan-made T-shirts ("Space Vikings - Beer planets are the best!" etc - vanished?) and Shrapnel has offered mouse mats, posters (and maybe mugs? or am I making that up?). The mouse mats are still on sale at
http://www.gamersfront.com/cgi-bin/s...?Category=9800
PvK