We have a bolt and nut supply place here in SLC Utah that I can buy those from. There nothing more than a bolt that meets a spec so you can buy those from anywhere that sells that spec of bolt. I think I was quoted about 10.00 for all of them or so.
Here is they are if you do not have a similar place near you. Maybe you can ask them to ship them to you.
Bolt & Nut Supply Co.: Homepage