All of yall are talking about a single 5850, I'm assuming. I was wondering about 5850 in crossfire...
Both cards will fit, and it's a great case.
Now for the stuff you don't want to hear: Both cards would be so close together that the top card will run very much hotter. Automatic fan controls will probably keep that from being a problem so long as you don't overclock. Still, running two cards would force x8 mode, which will hurt your performance by around 5%.