Try what Fish said. If you can't find one call Boat things. Their number is in the phone book. Ty Clarkston is the guy that repairs the motors. he also has parts for MinnKota and Motorguide. Great guy to deal with.
I've got a homemade bracket that came with a 1986 Sylvan 14 footer I had. If you want I'll dig it out and see if I can send you a picture of it. If you wanted it, you could just pay the shipping or send me any crappie related stuff, books, videos etc. that you no longer hadneed of.