What we did last year when we needed to do things like that, we walked into a Brafasco, showev them the part, and say we a longer one of this.
Brafasco is basically the Wal-Mart of fastners of ANY KIND.
I don't know if you have them in the US, but if you do, look them up. And even if you don't have them, I'm sure you have things like them.
http://www.brafasco.com