C.M.
I agree with Mommy G. I have the Evenflo Triumph Advanced DLX Lincoln for my 18 month old daughter. i too intend to keep her rear facing as long as i can. she is actually small, as she was a preemie, so i wanted something i could keep rear facing until she was big enough. it is easy to adjust the straps and i also did research before buying and it was on one of the consumer lists of safest convertible car seats. it was also in the 2009 Car Safety Seats guide from the American Academy of Pediatrics for car seats that meet the federal safety requirements. I'm putting the link for the car safety guide so you can see all the seats that meet the requirement:
http://www.aap.org/family/carseatguide.htm