JailBird Cage with an Integrated Lock

Alright, I spent some time recently in an affordable Chinese cage. It featured a hinged base ring which made it easy to slip on, though it did pinch underneath my testicles! The locking mechanism was the usual tumbler type. She really liked turning the key and walking off. Last year I went back to JailBird… great fit, comfortable ring, everything seemed fine… except she isn’t fond of the screw - it’s a bit fiddly for her hand strength, and she’s doubtful that someone could unscrew it by accident… So here is my request. A custom-made cage in the JailBird style but with an integrated lock (so it doesn’t protrude too much or create a weird bulge under trousers while I’m at work)… any suggestions? (Additional notes - no padlocks because they dig into her, and yes I have a PA if that’s useful…) Thanks for your input!!