We haven't heard from Mercedes on this one, but its sweeping the Mercheads community like a superstrain of mono. A track-only McLaren Mercedes SLR 722? Why yes, it's the GTR, and according to accompanying signage, it's 661 pounds less than a typical 722. It's a ready-to-race model in the vein of the Ferrari FXX. Apparently, only 21 are set for production, at 775,000 Euros a pop, and will likely be sold only to hardcore Mercedes insiders. [Carpassion via Supercars.net]