they are artillery wheels, lots of different makes and sizes, hopefully someone can give you more info. Oh and i believe someone is now making repros.
You can buy the Chevy or Plymouth version from a Hamber Wheelkid for about $75 each. I recommend the Plymouth wheels because they are 5 on 4.5 bolt pattern and work on popular 8 and 9 inch ford rear end bolt patterns. The Chevy wheels are 6 bolt and can be used with adapter plates. Go to http://www.rallyamerica.com/usedwheels/dodge.html