Author/Agent Mandy Hubbard has some interesting links on trends in MG and YA fiction. Also, if you didn't catch it before, she breaks down how much an author makes with a traditional publishing advance.
Dystopian is the new hottie in YA. Agents and editors are prophesying that MG will be the new YA, and sci fi will be the new dystopian, so apparently the big money is a breakout sci fi MG novel. That's great news for me, because I've got nothing remotely like that, although I am working on a chapter book about a Dragon Doctor.
Just remember, when you actually go to write, that the two things you must never, never think about are (1) Chasing Trends and (2) Making Money.
I don't know about you but I obsess about those those things all the time, and it's like eating ho hos to lose weight, which, yes, I've also tried. Nothing is more guaranteed to scare off my muse than demanding to know how much money she's going to make me.