Have you found anything worthwhile yet? I'm looking for a book that suits your criteria as well Most young adult books I've come across these days are written in a really immature voice. (I guess that's how they've always been, but I wasn't bothered by it when I was younger). It gets even worse when the author constantly swears in an attempt to relate to their teenage/young adult readers.
sigh It seems like I'm getting old
Currently, I'm reading a book called "Une Boutielle dans la Mer de Gaza" ("A Bottle in the Gaza Sea"), which covers a series of emails between a young girl from Tel Aviv and a slightly older boy from Gaza. I'm really enjoying how it portrays their perspectives and highlights how government and international relations don't necessarily reflect the views of citizens.
I'm about halfway through the novel, but I must point out that there have been a couple of offensive/questionable statements made regarding Muslims and Arabs in general, but aside from that, I think the author does a decent job of dealing with a sensitive issue.