I've had this sling bag from Caselogic for three years and it's been a stellar performer. After all this time, not a tear or any malfunction.
It's incredibly comfortable to wear all day. The weight is distributed very well. The sling swivels very easily around to access the camera. http://www.caselogic.com/en-us/us/products/camera-cases/dslr-camera-bags/slr-sling-_-slrc_-_205_-_black
It won't hold a Pro camera or an APS-C with a grip. The 7D should be totally fine. The side pocket can hold many sized lens. I believe I've even gotten a 24-105 f4 in there. If you don't carry a second lens, you can fit an iPad mini and other little items! That comes in handy. There is a system that allows you to attach a tripod. But with a camera and extra lens/iPad, the sling starts feeling very heavy for it's size.
I love this bag and still use it regularly. Great for small events, hikes and discreet enough for street photography.