Ok, this isn't a new idea. Brian Setzer has done it, Levy's makes one (but it's plain, generic, and has no retro-cool-mojo-factor).
I went to the local pull-it-yourself parts yard yesterday and picked up some seatbelts. I am going to be making these into guitar straps.


I'm still working on getting them cleaned up (GM uses this nasty putty stuff around the bolts, and some of it got on the straps on the way out).
I'm also trying to figure out a good way of attaching to the guitar lol. If you have straplocks, you can just hammer the end tabs flat and bolt them on, but I'm going to figure out a way to clip them on to a regular one, too. I think the only way (without having to pay someone to sew leather tabs on the ends) is to replace the strap button with an eyelet bolt, and use a little carabiner clip. Easily reversible if you ditch it.
I just thought I'd share. If anyone wants one, let me know. Right now I've got two tan GM ones (keeping one for me), and I have two black Cadillac ones. I plan on going back in a couple weeks to find more of the same, and maybe some Chrysler/Dodge, Ford ones, too.

Sorry for this pics, they're from my phone. I think my camera's at work. Or in my car. Either way, it was too far away to go get lol.
I just wanted to share. Comments and ideas are welcomed.