Cars

Angeleen - A huge range of American automotive designs.
http://www.angeleentshirt.com/

Ferrari Shop - Includes apparel, accessories, model cars, memorabilia, games, and books. Delivers all over the World.
http://www.ferraristore.com/

Raw Horsepower - Embroidered apparel covering hot rods, trucks, bikes, and performance vehicles.
http://www.rawhorsepower.com/

hatsandtshirts.com - Dale Earnhardt and Jeff Gordon themed shirts and caps.
http://hatsandtshirts.com/

Moondog - Hot rod shirts, hats and stubby holders.
http://www.moondog.net.au/

burnoutgear.com - Shirts featuring American muscle cars.
http://www.burnoutgear.com/

October - VW Beetle and camper themed shirts and accessories.
http://www.october.co.uk/

Car Stuff Accessories LLC - Screen printed and embroidered T-shirts featuring cars, and dogs.
http://www.cstuffacc.com

The T-Shirt Guy - Automotive related designs, mostly from the USA, but with some European vehicles included.
http://www.thet-shirtguy.com/