what you have is a personal issue with your own success or something along those lines.
Get over it.
The only thing you should be worried about with a lettered truck is your guys or you doing something stupid like parking it at the strip club or something like that.
Well that and getting a good design.
My advice, just do it. Any problems that come up, well that is what insurance and the cops (or a large caliber hand gun) are for.
If you don't know your costs, you can't bid right. If you don't bid right, you can't make money, If you can't make money, become a Wal-mart greeter.