For some basic pics of the tire rack visit:
http://www.robsherrard.com/events/redhook
I made the rack myself and I don't have any other pics just yet but i can get some later today or tommorrow. The Rack fits directly into the 1 1/4 in. reciever of the hitch and is held in place with a normal hitch pin. The Rack itself is about 2ft across and about 16in deep. It sits about 5in behind the rear of the car and about 6in from the face of the hitch. You can stand between the rack the car to access the "trunk" area. It is an open design to save weight as the complete rack is only about 15lbs.
I have tested the rack with 2 rear stock sized/weight tires with Hoosiers mounted with a total weight of about 75lbs. I designed the rack to hold 2 tires as i can fit the 2 fronts inside the "trunk" area.
I plan on designing another system to hold the weight of all 4 tires in the future. Most hitches for cars are only rated to 200lbs and i believe a different system is needed to hold the weight of all 4 tires.
I am not sure of cost just yet, I would have to add up the reciepts (something i never do with racing stuff...) but i do know it costs/weighs less than the commercially available type.
Will
btw: what type of rack to the miatas have???