This would be a good item for us to bring up in an episode on Valyrian steel, which we'll surely do some day.
I am guessing there was such a thing as Valyrian steel armor. The elite Valyrians were insanely wealthy, I would think. The forty or so dragonlord families had a monopoly on dragons, and a huge empire. They had untold numbers of slaves who were used in their mines, and thousands of years to build up wealth.
On top of that we know that Valyrians had sold a few blades to Westerosi lords(and thus, probably, elsewhere in the world as well) before the Doom. These were traders who sold the blades, and we are told dragonfire is part of forging(not reforging, which a few like Tobho Mott can do). In other words, the traders and merchants weren't making the blades on their own. While it's possible the traders were selling these on behalf of one or more of the dragonlord families, it seems likely that there was a good amount of it. I suppose the stuff never breaks, so over the thousands of years they could've built up a quite a lot, collectively.