This is not actual help -- I used to read travel books rabidly but haven't for years. However, if you don't find what you need through LJ, could maybe a library help you? They (should be) happy to help find out what's been recently published, have all the publication info, maybe some of the books themselves; I don't know, maybe even something that has some reviews, or some such.

That probably doesn't help -- good luck! (And also, WTF? The agents basically make you do their own job for them? Huh? They're supposed to be the ones up on what's been published, aren't they -- not you? You're, like, supposed to *write* -- not do their work for them...::exits, with eyebrows raised heavenwards::)