That is exactly what my boss does, and I assure you, there is NO extra money to buy subwoofers, chrome plating, extravagant paint, and other gee-gaws. That is a big investment.
My point is, which contractor will charge the school administration less... the one who has stock busses, or the one who has invested thousands, if not tens of thousands, into a rolling custom truck show. I don't think it takes a degree in business management to figure this one out.
Don't get me wrong, the busses are cool and all, but that stuff is coming (read: $$$) from somewhere, and I doubt it's from the SAU or the taxpayers.