I think it came in a Warhammer 40K Chaos Defiler kit. One kit from Warhammer 40K will give you lots of great bits. They are expensive, but the right kit, like the Defiler, will go a long ways!
I've always wanted to build a Mini Cooper with the legs of the Defiler, but then again, I've already done such a thing in another build . . .
Just keep the imagination juices (Cranky Juice!) flowing!