According to Turkish tech site Donanim Haber, nVidia will launch it's first Dual-GPU card based on Fermi architecutre on PAX East 2011 event in Boston, MA. For those not in the know, PAX East is taking place between March 11-13. The card is based on two GF110 chips which are currently powering GeForce GTX 580 graphics cards. Thus, you can expect to see 512 cores, dual 384-bit memory controller, 3GB of GDDR5 memory and more importantly, three DVI outputs for single card 3D Vision Surround Gaming.
In order to create the GeForce GTX 590 Ti, nVidia went with full shader configuration and decreased the clock of the components until it fit the power budget - you have two 8-pin ports for 300W and additional 75W drawn from the motherboard for a grand total of 375W. Given that a single GTX 580 graphics card has a power limitator which controls the card not to exceed 200W power draw, we'd expect that clock restrictions are fairly low and that this card should not be much slower than two discrete GTX 580 boards in SLI mode.
There is also a question of when dual-GF114 (GTX 560 Ti) card is going to make an appearance (at least in semi-supported custom versions from EVGA, Asus and Palit/Galaxy/Gainward), and we would not be surprised to see the launch of more dual-Fermi cards over the course of 2011.