It is May 17-20, 2012.
Has the date been announced yet? Botcon is in Dallas this year too, so there's the possibility I could combine them for maximum exhausto-fun.
I found this in the ReaperCon forum from the last time it was asked. I had to filter the results to show more than 30 days, or a search would also work. I also checked under the ReaperCon link on the front page, but that said something about the 2009 event being over.