Hence, the big boy seat. That seat will go to 20 pounds rear-facing and to 40 pounds front-facing. We decided not to use the high capacity seats (to either 65 or 80 pounds) since he is below the 50th percentile in weight, by that time he'll probably want something different and a simple booster seat doesn't break the bank.
After beaucoup de research we settled on the Britax Roundabout 40 in a tan color, matching the interior color of the 06 Fusion. Niels put the seat in already and tomorrow we'll swing by the North Canton Fire Department for a safety check as we feel it doesn't fit entirely snug yet.