Most of the stainless steel chains I've seen have been wallet chains - you're definitely right about their rarity, El-ahrairah. Which is unfortunate, because it seems like a truly superior chain technology.

On the topic of nickel-plated chains, I don't know if it would be rust-proof, but it would certainly take a hell of a lot more to rust it. If applied properly, the nickel should stay on.

Of course, that's in theory. I don't know much about practical applications.