Movable Outdoor Sign for back of truck

[vinylink0331]

Here is the deal. We have a customer who owns a Ford car lot. He has some of his vehicles on the DOT's property. It is off and to the back of the lot. It is located right beside a highway that gets a lot of traffic. They know that he has his vehicles there and are probably not going to ask him to move them any time soon. We originally were going to do a permenent sign for them until we found out about it being DOT's property. Now the client wants to put a sign in the back of one of their Ford trucks out by the road. He wants it to be something movable and something he could possibly put up by himself.
Does anyone have any ideas on what we might could come up with?
In my opinion, we should ditch the back of the truck deal. Seems dangerous. I was looking at some of the outdoor exhibit type expandable banner holders that can get up to 96" x 96". It has the footing that you fill with water or sand. Any suggestions would be greatly appreciated. Thanks.

 

[J Hill Designs]

4'x8' A-frame setup that gets tied into the pickup mechanically somehow?

 

[knifemaker3]

Wrap the truck

 

[jfiscus]

Anything large need to be secure... so if he wants something large, it needs to be mounted well. Something smaller would be more portable; but can anyone see it from the highway?

Maybe a larger sign installed further back (on his property) or as stated; wrap a truck or box truck for a larger "portable sign".