I finished Under Heaven by Guy Gavriel Kay this morning, so I get to roll today:
This is going to be tricky. The only one that immediately comes to mind would be Ken Catran's Deepwater Black. There is The Bromeliad Trilogy by Terry Pratchett but I'm not sure if I feel like it. Or I suppose there's Podkayne of Mars by Robert Heinlein. Maybe Little Brother by Cory Doctorow?
Unfortunately I haven't been keeping up with listing my ebook library on GR so I can't just search for what I've shelved as YA there (well I can, but I'm obviously going to be missing a lot of books).