Hi Al
I've had three backpack style camera bags (all LowePro) to hold my equipment over the years as I've added new lenses and bodies. I've never been worried about the camera/lens setup pointing lens down, but as mentioned above, I don't plan on dropping the backpack any time soon! My current setup involves a 7D with a long lens resting with the body on the 'bottom' of the bag and the lens pointing up (when the back is standing up on its base), and then a 5Diii with a shorter lens pointing lens down, nearer the top of the bag. This makes it very accessible when I stand the bag on the ground. My current bag is a LowePro ProRunner 450AW if that helps. The extra depth was essential because both bodies are gripped and the space for the laptop is handy if I am away from home.
HTH
Neil