Your best bet is to draw up what you want and find a friend with a welder. Or pay a welder to do it. Its a pretty simple job, just 2" or 3" pipe depending on what you will be mounting, some nuts and bolts and some flat stock. Buying one from a taxidermy supply company like McKenzie will cost you more in shipping than having one made. If you are not sure exactly what you want swing by a few shops and see what they are using and get some ideas.