I really like the hinged shelf solution, rattle as it may, as we'll have to keep the 2nd row seats in the truck with the grandkids going with us. Nice job!
Even so, with one of those damn Nascar roll-cage baby seats it's going to be a pain until the little guy gets considerably larger. Question for you, though - how were your door mouldings attached? Mine aren't falling off like yours. I'm just wondering what's involved in yanking them off before I ruin a paint job underneath them. Thanks!
Edit: May have just solved my own problem. I could build the platform so the hinged portion is divided at the hinges. Since he won't need the full length of the platform for a few years, I could just flip up the one rear seat that doesn't have a car seat in it to give me room and leave his side with his car seat alone. Once he's big enough for a simple booster seat, all those issues go away.