Unlimited vendor stock

I just noticed that if you buy an item from the vendors, they seem to have an unlimited supply of them. Specifically I just found a level 3 sword with 15 damage and was able to buy at least 5 of them. I think they should only have 1 of each item(with the exception of things like potions obviously).

It might not matter much now, but if they sell rares later on...all you'd have to do is fins one game where a vendor just happens to be selling a rare with perfect stats and you could buy dozens of them to sell off on the RMAH. The only limit would be how much gold you have(or are willing to buy to invest into it, since a good rare will certainly sell for far more than the vendor's price worth of gold). Even inventory wouldn't be an issue since you could just get a friend to join and hold the game open for you then switch to another character.