Yep, what little I've learned about those wheels was from going to a few swap meets (sticker shock!), a couple mentions in mag articles often in relation to the milk wheels, and on the HAMB. I realized that there were a lot of different wheels, all of them were fairly rare (expensive), and that you rarely found a full set. They also are not sized for modern rubber, so unless you are willing to buy them and then cut them up, your tire choices were very limited. This may not be an issue for you. There are some companies that offer new ones, but they are not the same as the old Mopar style.
On HAMB, there are more threads on them. 13 pages worth!
http://www.jalopyjournal.com/forum/search.php?searchid=5457298