The file I used worked great on my wood cnc router machine with no modifications to the file at all.
I used pine laminated board for this from home depot, so it would have turned out even better if I used hardwood or laminated up #1 pine myself. Approximate size is 25.5"x15 for this sign.
So if you have a cnc router, head to http://www.customdxffiles.com/ and check out the stuff

Thanks Jason