In reply to ffati:
My Fuji x100s goes into a ThinkTank pouch which is then hooked via a carabiner around the base of my sack's shoulder strap where it sits out of the way at waist level. When needed, it can easily be slid up the strap to access.
It's also very handy if you need to leave your sack unattended for a short while as you can quickly unclip the pouch and take it with you.
Post edited at 20:15