if this is true,there sure are a lot of folks buying a lot of new f350's these days im sure without a CDL lol.and a LOT of previous buyers who bought F-superduty (pre '99 F450 if you will.)
http://www.ford.com/trucks/superduty/specifications/payload/
i see you placed "tow vehicle" in bold,so perhaps this is where im confused? whats the definition of a "tow vehicle"?
i can't image a CDL is required for a light duty truck,nor this van posted in the first post.i just can't.
if that was the case,how would U-Haul be in business today lol.there is no way on earth they'd let ya out of the lot with a truck rated for over 10k GVWR (like many of them are,and then some.and we all know,people load them FAR beyond that little door jam sticker.

) without proof of a CDL of course.