(Originally posted at http://joelnoche.multiply.com/journal/item/107/Mars-Rover-Curiosity on August 4, 2012 6:33 AM)
According to this article,
The real rover is set to touchdown on the Red Planet early Monday morning (Aug. 6) […]
The Hot Wheels 2-inch long by 1.5-inch high by 1.25-inch wide (5 by 3.8 by 3.2 centimeters) rover is so far the only toy or model version of Curiosity to be announced.
(However, a 1:20 scale model built out of LEGO blocks has been created by Stephen Pakbaz, an engineer involved in some of the design and testing of the actual Curiosity. See this article for more information.)