I use the
National Geographic Large Camera Canvas Backpack (NG-5737) because there is no TB option. It's actually as close to the feel of a TB bag as I found. It would indeed be great to find a TB bag like that one, only that was sealed and much more water proof'd. For now my bag is treated with Nikwax Cotton & Canvas, still it has a lot of openings that would let 'determined water' inside for a visit.
BTW, cool news on the bag insert. It's a nice start for sure. Combined with the other the right TB bag and a few utility pouches it could work as a carry bag for a casual walk around kinda shoot. Which I am guessing is the idea behind the design?
Darcy: I carry a Sigma 150-500 lens (almost 4lbs) almost everywhere I go when outdoors and I don't see it fitting in the camera insert while mounted to my 40D. I also bring along a Sigma 180mm macro (a bit over 2lbs) too...what is the largest lens you have carried in the insert? What I would really like is a Buzz style bag that allowed a about 3 lenses, a body, a flash and the ability to attach or store inside, a couple pouches for other accessories. Just a full on grab-n-go solution. None of the currently available sling type camera bags are worth a darn, mostly because they got the whoulder strap wrong...it's too narrow at the top so if you have a could heavier lenses in the bag the weight is distributed across a wider area.