Like you say, the shooting on the fly thing is great and for sure a lot of people have been doing it for years. Here are a couple of more things that may be helpful.
I like to use a waterproof camera so I can keep it "exposed" for easy access. When doing dirt rides, the waterproof model is great as there is protection from both dust and water.
For dirt rides I use the gearkeeper and keep the camera in a partially open pocket on my vest. The quick access makes for getting some nice crash or post-crash shots as the camera is so readily available.
When not using the vest, like on street rides, I use a belt case with a magentic flap. This allows you to draw, arm, and fire the camera with one hand. Again, the waterproof camera makes it no big deal to carry the camera "exposed" to the elements on the belt. If there is no other spot to connect to, a key ring can be connected to the jacket somehow for a place to snap on to.
Hope this adds to the already great information posted here and helps out some others.