Just reposting the post i submitted on DIYphotography.net
Here is a quick R-Strap recipe by Hee Soo Shin:
1. Take a strap from a messenger bag. You can take one from a bag you no longer use, or buy a new one for close to nothing at goodwill.2. For this hack, Hee Soo, took one of the quick connects by Bogen tripod, but you can also use a 3/4 bolt with an extension. Or,
you can use an L bracket from the bottom part of a cactus v2s receiver mount.
3. Use a buckle to fasten the two ends of the strap together...
4. For shoulder pad, you can use what ever came with the messenger bag strap, or use a shoulder strap pad from a guitar store(7 bucks))
Voila... DIY R-strap.. it's super comfortable and the great part is at weddings when you have to have 2 camera's with flashunit in the hotshoe it's totally out of your way and you don't have 2 flash units sticking up at you.