This is the company I was going to recommend. It is The Slinger Strap, not Comfort Strap. They now have three straps, The Slinger Strap, which is waist strap only and you must drill one hole in your instrument to attach it (least weight on the back); Sling Strap, which is combo waist and shoulder strap (I use this one and can be seen in a video on the site playing my Alembic); and the brand new Harness Strap which has two shoulder straps and a waist strap. I believe having a waist strap is key, whichever strap you choose. It takes a lot of the weight off your back and neck, like hiker backpacks do.
http://slingerstraps.com/