http://www.oobject.com/category/vehicles/ this has a lot of great stuff, from the top 15 Harley Earl designs, to monster harvesters, to vehicular snow machines http://www.oobject.com/category/10-strange-snow-vehicles/ and Pininfarina design http://www.oobject.com/category/classic-pininfarina-designs/ this website is loaded!
Serious time wasting potential!
Enjoy!