As described here, my 4-A rack ends grew out of a much simpler design that I had watercut out of stainless steel plate in 2010.
As it happens, I've got about 40 of these little guys left, and I'm glad to offer them as "cherry on top" rewards for anyone who backs my Indiegogo campaign. If you're a backer, I'll offer you a 50% match on these parts. In other words: you buy 16 of my 4-A rack ends, and I'll give you 8 of these plate ends. Just shoot me an email and tell me how many 4-A ends you've pledged for, and I'll add these to your order for no additional charge. I've only got a limited quantity of these, so give me a holler soon!
These are actually pretty great rack ends, and I'm sure that plenty of builders would get good use out of them!