Buying a gear backpack?

I need to buy a backpack for my photography gear, but I can't seem to find any that fit these requirements:
Has to fit a Nikon d3200, with the Nikkor 18-105 and an Opteka 6.5mm aspherical lens.
I will be flying quite a bit, so the backpack will have to be carry-on size
I also want room for other stuff besides photography gear (some snacks, ipod charger, etc)
and possibly some room for a gopro hero 3, its case, battery, and a mount or two.
An added bonus would be a tripod/monopod carry strap, but this isn't necessary.

Try the Think Tank Streetwalker, or if you want a little more room, the Streetwalker Pro.

http://www.thinktankphoto.com/products/streetwalker-backpack.aspx

http://www.thinktankphoto.com/products/streetwalker-pro-backpack.aspx

Or if you also want a laptop, the Think Tank Streetwalker Hard Drive.

http://www.thinktankphoto.com/products/streetwalker-harddrive-backpack.aspx

I have the Streetwalker Pro, and I can get a ton of stuff in it; a D90 with a massave Nikon 80-200mm f/2.8 attached, plus 4 other lenses, speedlight flash, extra battery, cables, charger, etc. As well as an android tablet.

Here is a video for the bag:

And it is carry-on capable for both domestic and international flights.

This is my bag.
http://tamrac.com/5606.htm

I understand it's not what you're looking for but this company makes excellent equipment.