Design me a Sounder bracket

I need a special bracket designed for Lowrance and Hummingbird sounders. The genuine brackets break. 6mm aluminium required (or if you recommend another material) as I want these brackets to be heavy duty. The tricky part is I want the sounder to be made lockable so people do not have to remove the sounders from the boat when boats aren't being used. The lock design must be marine durable, very hard to break and look good, not even noticeable would be good. The bracket must also look great! I want people to buy them not just because there heavy duty and lockable but because they look awesome! they have to be designed so manufacturing costs aren't to high so can be sold on. Also lock design must be very good as I don't want anything that could cause warranty problems. Will pay good money for quality designer!