Hmm....I've just bought some Eheim 12mm quick (dis)connect valves. Is that the sort of thing you mean? They haven't arrived yet, and I've still to set up my water cooling (Uni got in the way) but I'll let you know what they are like when they arrive.
They should be perfect for the job as, I'm sure you know, Eheim make their stuff for fish tanks. Here's a link to the thread that alerted me to them:
http://forums.procooling.com/vbb/showthread.php?t=9482
I got mine from a store in the UK. If you want it, let me know. I dunno where in the US you could get them. Search on Google.