Ah...
I know Reg's are solid (just saw them) but think of a 'cap' that could be added like this... but they all don't have to be as fancy...
And dabears: Um, so they make 'em that big? You're looking at bigger than an inch in diameter... I don't think I've ever seen snap-covers that big. DIY button-making, yes (yanno, pin-on, etc) Gotta pic or source?
There... finally got image to show up... and sweet work Reg, VERY sweet.