None of the 5000 serires cards can do that without a catch. And the catch is that the 3rd monitor must use the Displayport output, so you could use an adapter to get that other DVI or HDMI.
Ya, I dont think the OPs after eyefinity but most of the time when people ask for multi monitor setups/upgrades they are limited to only one PCIE slot. But we shall see when he replies back.