One possibility are the sling bags.
I like the idea behind these bags as they have only one strap and can swivel around the body so it can go from the back to the front for quick, easy access to gear. I've got a bit too much gear for these bags, but it might be something that might work for you.
See these links:
Lowepro: http://www.bhphotovideo.com/c/product/3 ... amera.html
Tamrac: http://www.bhphotovideo.com/c/product/4 ... Sling.html
Both manufacturers offer these bags in various models, so you may want to look at others within these lines.