Website DannyChoo.com recently visited a Tokyo shop called "Maizuru" that specializes in selling shokuhin sample. Most restaurants work closely with plastic food makers to accurately reproduce their dishes; however, they can still buy shokuhin sample from shops like this if they need to in a pinch—ditto for the general public!
Shokuhin sample food is not cheap, with many dishes costing over US$70—or much more.
If you are in Tokyo and want to visit Maizuru, it's located in Kappabashi Street, which is filled with cooking tools and restaurant needs.
Have a look at the delicious fake food the gallery above. There are more pics in the link below.
Japan Plastic Food [DannyChoo.com]