@x56h34,
I think you have a good idea here and it will serve the Amiga community to have these higher wattage, more efficient, better cooling PSU's available. Given what you wrote on how you plan to accomplish this task, why not try to find as many dead or dying A3000 & A4000 PSU's and take them apart to use the housings again. Then offer a discount to those buyers who send in their old PSU's so you will have a constant suppy of original PSU cases to do your conversions.
If reasonably priced, you can count on me to buy a couple of each, I currently have 3 of each A3000D & A4000D, but doubt that I will be keeping more than two of each in my render farm.
Good Luck