Keystone Locomotive Works makes nice palstic and metal EMD cab interior kits. They are fairly generic; they include a pair of seats, control stand, front and back walls, speedometer, and heaters. If your particular prototype had any extra options, like extra/different styles of seats, refrigerators, radio gear, etc., you'll have to scratch it on your own, or check other manufacturer's part lines for something close (I know Precision Scale offered a few diesel cab interior parts). Here's a Walthers search page showing the Keystone cab kits: http://www.walthers.com/exec/search?category=&scale=H&manu=395&item=&keywords=cab+interior&instock=Q&split=120&findit_butt.x=87&findit_butt.y=9
