My local hardware has a board with springs on it for comparison. There must be 50 or so there, with bins around the corner for each type. Haven't seen that type of display at the big box hardware places. With the dimensions you posted above, I could probably find one that's pretty close. The other option might be to buy some spring wire and build one yourself. It would take winding the wire around a correctly sized dowel to allow for springback, then forming the end hooks. If I were to try that, the first attempt would look pretty ugly. LOL!
