If you're a fan of Nascar, Transformers, and M&M's you might be interested in the Kyle Busch #18 Diecast car that is for sale. It's the person's car with Optimus Prime colors, Transformers 2 logo and the M&M TF characters. Buddytoy's has it for "sale" at $62 for those interested. Sadly the car does not transform.
Update: Turns out that the above car isn't the only version that will be available. A 1/64 scale will almost be made and can be ordered here for $5.50. I don't know much but I am guessing that size is about Matchbox sized.