Best way to match common protoboards to NEMA-rated enclosures?

Just a random thought, but is there a good way to find mass-manufactured protoboards in various sizes and with mounting holes which match commonly available NEMA weather-tight enclosures, like from BUD Industries?

I have been using Imps in somewhat hostile environments and love the range of sizes of weathertight enclosures available. However, I have not found a comparable range of protoboard sizes designed to fit inside. Is that because the world as it is wants me to design a custom board to fit inside?

Or, am I being an idiot? Meaning, is it really easy to find a standard NEMA 4 enclosure with standard mounting posts (dimensions) such that I should be able to find a basic protoboard which fits in perfectly?

My dilemma is that I need to make a few dozen, more likely up to maybe a hundred or more, basic boards to fit in weather-tight enclosures, to accept an Imp via headers and have a bunch of screw terminals available for sensors. I would love to say that this is going to be a mass-production job, but it might not be. So, I can’t assume quantity discounts on a primary board to sit inside an enclosure.

Again, am I being an idiot? Or, is this just reality?

Seems like a good application for a custom pcb. Why not do that and use one of the sources such as (usa), (china), etc.?

manufacturing would then be quite a bit easier. or, have I misunderstood something in your request?

No you did not misunderstand my request. I think you hit the nail on the head. Thanks for your input. A custom board is needed. I suppose I was just trying to see if some other premanufactured options exist.

I contacted MakeDeck and they are INCREDIBLE and for now I’m going to see if I can work through a solution using their help. I can’t say enough good things about joel and MakeDeck. joel is awesome!