The only one I've heard of is Trista, and that may be nothing more than a modern invention. As for Tristania, I've only heard of it as the name of a Goth/B&B band, although they quite probably took their name from Tristan. I know nothing more about it.
For what it's worth, I agree with Miranda 100% regarding "baby name books" and especially Mr. Bruce Lansky. His work is actually comical at times for the sheer audacity of the inaccuracies.