Hmmm, there doesn't seem to be a lot of interest in a group buy at this point. I can't imagine that this is gonna be on sale for much longer. Maybe I should just pull the trigger and buy the single copy like Xealot42 did.
I think I'll wait until just before 1PM EST (when Steam's sales usually change over) and see if a group buy materializes. If it hasn't by then, I'll just pull the trigger.
Edit: I went ahead and bought a copy, so I'm out of any further group buy.