http://snowboardrobot.com/backpack-reviews/dakine-mission-photo-25l/
It might not be as clear in this video as I want, but this backpack can hold a lot of stuff.
The most I have had in there at once was two DSLR's, one ready to go, the other just the body, 3 lenses, battery grip, charger, 13inch macbook, goggles, sunglasses, writing pads, phone, water bottle and a gopro with a bunch of accessories. And a snowboard on the outside. I was quite impressed, but I have a much better write up on my site at the link above.