I finally got something together. I couldn't decide on what to do, actually I had idea overload, vintage cowboy prints, colour schemes, simple illustrations etc, etc, but once I re - read the brief it all became quite clear. I had to use Woody! I wanted a Wild West look without being too tacky.
After lots of searching the net for Toy Story western ideas I found a poster used at one of the Disney parks for inspiration and got to work in Photoshop to come up with this...
This is the original Disney Poster (photo from Themeparks.about.com)