Where should I look for an empty dive watch case with 2 crowns?

I'd like to change the case on my watch, from a Turtle with no outer bezel to a dive style with external rotating bezel. However my movement has an alarm, and so it has two crowns… one at 2 O'clock and one at 4 O'clock. Where should I look for case with holes for two crowns?

Thx.