If you have a lathe and a block of aluminum you can make one yourself..... That's what a friend did for me when I did my gen2 rad conversion. I was gonna order the 1 from RCC but it was already the weekend and my friend said he could make 1 faster than it would take for them to ship it.
So that's really your 2 options make 1 or suck it up like John said and buy 1. It's not like it's even an expensive part.... Less than a $100.