HarryA, I like it. No board dimensions, but at that low a price, it is worth a shot. You are right about the 'cute' factor too.
Kellys_eye, yes, there are 'standard' boards. I was taught that in our Army. That is how we ordered and maintained our stockage. And they are often US/Metric combinations, such as these. I just snatched one out, 'PY-5CM*7CM', Grabbing a ruler: 2"x2.75", Grid is A-X, 01-18. Mounting hole spacing are 1.75 and 2.5 inch. Through hole. Seeing your location, it might interest you to know that the UK services use such, I was stationed there for a bit, High Wycombe. I also remember a crown marking on those.
Dave9, I have found quite a few with battery compartments. 9v, AA, AAA, cr2032, etc. As to the lack of power wiring, springs, etc, one adds a battery 'pack', wires it in, and glues in the pack. SOP. But again, with no board sizes, chicken-and-egg.
I am still looking as I have a LOT of these boards. I did find one seller who has the board dimensions. I am working through that site now. PacTec. Hope that helps somebody.
Alternate question: I also used to use glue into the box screw standoffs, and I have a 'superceded' NSN (national stock number) for them. I had issues with the glue not holding, but could be made to work. Anyone have a reference / source for them?
(A stray thought hit me, this would be a nice 'cottage' industry. 3-D design and 3-D print, send prototype to pacific rim for them to manufacture, and sell here, Shame I do not know 3-D)