John
Are you looking for someone to make a foam copy from a 3D CAD drawing, or from a 1:1 physical model made out of some other material?
If the latter, I can't help you directly, but you should be able to find a local engineering shop with a 3D digitiser (either probe or laser (depending on the resolution you want)). Once plotted, your 1:1 (or smaller) model is imported to CAD for modification (or scaling) and then sent off to CNC for machining out of foam or something harder.
The great thing about this process is that if your original is symetrical about any axis, you only need to build half of it, and it can be any scale you want!
I hope this helps.