Well, as I've said to others with more than 1 carseat who want a 3rd row, a minivan is your only practical option. Reason being that, with carseats on both sides of the middle row, you would have to remove the carseat to be able to fold the seat forward to gain access to the 3rd row. This is something you obviously don't want to have to do all the time.
So, you need a minivan and you want AWD. I think that pretty much narrows it down to the Toyota Sienna, if I'm not mistaken.