i think the Hang'em high halo map (huge grey-ish map with 2 teleporters) would be ideal for this kind of server? in gg it's too slow paced and huge, but it might actually work out here considering you can have spawn points all over.
(sorry i dnt have the map link and actual name memorized, but it's on our gg server)
also, gg_octasky was removed from gg because it was a big map and slow paced,
i think it might work here too, im suggesting it before actually officially posting an [add] thread since already had it before :
http://cssgg.gamebanana.com/maps/145097