I seen another possible candidate sticker idea. I was at a stoplight behind a trailer that had these on the doors:

http://www.compliancesigns.com/ODE-1306.shtml

Perhaps this, with Enviromental waste management/consultants theme ??

Not a sobering thought!

I guess the trailers you guys use in the US are made from aluminium, which is a shame otherwise you could use a sheet of that magnetic van vinyl and get a custom design made for it - stick it on 'magnetically' when you want to, peel it off when not and roll it up and store anywhere (I guess a sheet of steel glued to the inside of the trailer panel would also make it work)

If not how about a three aluminium chanels riveted to the side of the trailer (painted to match!) to make an open ended frame, that would allow you to slide a custom graphic into place when you wanted to.

Just some ideas.

I was thinking of plastering this picture all over my trailer to keep would be theives out but then I might not want to ever go in there either

Yes will be there with the F100