It looks like the NVIDIA drivers have let another cat out of the bag. The 266.7x beta drivers list a GeForce GTX550 Ti based on NVIDIA's GF116 graphics processor. It's expected to be a 40nm-based design and feature a 128-bit memory bus, a TDP of 110W or less and should ship with 1GB of GDDR5 memory. Output wise it should include two dual-link DVI connectors as well as a mini-HDMI output.
It is said to resemble the PCB design of NVIDIA's GeForce GTS450 but since it carries the GTX branding it should have another kick in performance. Rumor has it that the GTX550 Ti is said to smack down the Radeon HD 5770 by a good 35% in DirectX 11 games and 20% in DirectX 10 games. Pricing wise we should see it at $200, roughly $50 cheaper than the GTX560 Ti.