MPS -
www.stangparts.com has sold them for like $200 each. I had a Mark VII spare for a while, but after changing two front flats and doing the rear tire shuffle, at work, in my dress clothes, I decided to get an extra Bullitt wheel and put it in the hatch. It sticks up about 3-4" above the well. I plan to get some foam padding to fill in the rest of the floor so it will be flat again and the carpet will sit flat. I saw someone had the wheel showing with the carpet around it, and it looked pretty nice to me. I might do that too.
I just looked, and MPS is now seling 05-06 17" spares for $50 each. I wonder if they would fit over the 94-04 front Cobra calipers? I'll have to ask my friend if we can try it out sometime.