Look in your local yellow pages for a "fastener" company. If you don't see one listed, contact a few professional mechanics and/or construction companies -- those two typesof businesses will use a fastener company regularly. A stud such as you describe should be a piece of cake for them, regardless of length. You can even get them with coarse threads on one end and fine threads on the other, if your application calls for it. You can also try to Google "fasteners".

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.