JonnyBoy wrote:The guy tried hard but missed virtually every shot - by the time he knelt down, selected his lens and set up his camera the shot was long gone
You mean that he put his camera back in its neat little aluminium case after every shot and then got it back out again when he saw the next shot?
Somehow I don't think that the guy is suited to wedding photography. Or wildlife photography, sports, journalism, candid, honeyeaters...
I'm suprised that as your trainee you didn't instruct him to carry his camera around his neck, turned on...
I guess your comments highlight an important aspect in selecting an appropriate carrying system, it has to be mated to the specific needs and style of the photographer in question. You didn't say whether or not the bag was to be used for day walks around town or extended multiday expeditions to remote places, whether you are into birding, landscapes, everything, etc? For example, I generally like to shoot landscapes and natures details so I can plan my shot in regard to composition and then wait for the light cooperate
It usually means being ready around dusk/dawn and it
usually means that I have plenty of time to have my gear ready to go and then I just sit around watching and waiting.
For daywalks, one of my friends uses a Lowepro slingshot, not sure which model, but as it only has the one strap it is easy to swing around in front of you and, with the side zip opening, pull the camera out and blaze away. It has enough room for everything that you could possibly want plus a rain jacket and water bottle. Might be an option?
Otherwise, for longer trips, I would take a good look at one of the f-stop gear packs like this one
http://fstopgear.com/en/product/mountain/satori-exp which I would consider if it wasn't for the hefty price tag or this one
http://fstopgear.com/en/product/mountain/tilopa-bc which 'might be handy as it is "Below the legal size limits for major airlines"
Theres a good review here
http://www.ianplant.com/blog/2010/09/26/tilopa-photo-pack-review/