I have a brand new Besttop Door Cart purchased from Quadratec for $245. Completely assembled and functional, got rid of the box, and low and behold the f-ing thing won't actual hold 4 doors though there are 4 spaces. Great cart to hold 2-doors plus accessories though.
$175 firm if you come and pick it up. I don't have the box to ship it otherwise I would have sent it back. I'll chalk this up to an expensive lesson in researching stuff more.
Ping me for more info.