Wow, I’ve been looking for something like this for years but I never knew what keywords to use to search for it. I have a backpack for my laptop and when travelling usually carry my camera gear wrapped up in clothes or paper but this should fit (with a little squeezing) into my backpack. I hope I can fit a Canon 40D and Sigma zoom lens in there with enough space for my Sigma wide angle too.
The flash can sit outside, it already has a padded cover.
I’ll update this post in a few weeks time with photos. You can find loads of these on Ebay.