spare tire mounting options on an 85 roof

I have been looking for a good way to mount my spare tire on the roof for some time. If you have any suggestions on who is making them let me know because all I can find that will work with out a full roof rack are rockratz and mopar. If all else fails I guess I will just strap it down to the luggage rack, if anyone has tried this how does it work, also if you have any locking ideas?

http://www.naxja.org/forum/showthread.php?t=19985&highlight=mount+spare Hasta

rockratz and mopar are the only two that I have seen. Plus finding a Mopar is going to be hard, but good luck.