I know you're not supposed to switch the car seat to forward-facing until they're two years old. But you gotta understand - my son wears a size 2T and he's at least the size of your average two-year-old. I checked the height requirements and he's very close. Plus, my husband plays rough enough with him on a regular basis that his neck has to be strong enough.
And then, this afternoon my mom went to put him in his car seat when he stood up in it and turned around to face forward, as if to say "I want to see where I'm going, Mommy!" I caved. I switched it around, and she graciously vacuumed the crunchy crusty stuff out of the car and car seat.
Another milestone. He was very happy as we drove home.