Shot Show vendors sell many products besides guns and ammo. It will take the best of four days to visit all of the vendors and look at their wares. On display will be all of the major (and some you never heard of) firearms manufacturers and there will also be an amazing array of hunting and shooting accessories, scopes, mounts, targets, clothing, ets., etc..
Point is, you don't need an FFL to go to the shot show if you sell non-gun items like scopes, mounts, knives, airsoft guns, reloading equipment, hunting jackets, boots, camping equipment and the like.
You will be required to prove you are in business because the Shot Show is a business show and not open to the general public. A business license or sales tax number issued in your name will work - or you can have a business sponsor you as their buyer or representative.
Go to the Shot Show 2012 web site and get the information you will need to apply for an admission ticket.