You can purchase or have actual rubber clothing made. However, many people don't deal in actual rubber and finding someone is going to be A) very, very hard and B) very, very expensive.
Your best bets are PVC and leather. If you absolutely must go with rubber, then keep in mind the following things:
It's hot. Rubber does not breathe or allow for the effective transfer of body heat. If worn, it can lead to dehydration and heat stroke.
Like latex, rubber will sometimes dry out and crack. If you find rubber clothing, be sure to ask how to prevent this.
I will once again say it is very expensive. A latex thong I saw in a shop once ran for about $25. A rubber panty I'd seen in a shop later on cost about $125.
Another possible consideration is neoprene. That's the stuff they make wetsuits out of. Other than that, I don't know what to tell you.