[Mitch Leland]

isn't builder's hardware more like... home door handles and taps?

Not necessarily... If you get into expensive cabinet hardware there's a lot of different kinds of latches and pulls. I was just trying to get you to think out side of the box.

A machinist could make this part. I appreciate you would like an exotic solution for a cheap price. The surround of the above part could be cut down to meet your needs. I think you're going to have to do some retro fitting to any part you get to fit your requirements. That is the fun part...