Hi recently my kit has been expanding so now I need a new bag for all my kit. Problem is I have a strong idea about what I want but am having difficulty finding it despite spending ages surfing the net!

What I am after is a bag for travelling. I need a 65-70L rucksack for my non photography gear which I could buy separately but I like the idea of being able to attach my camera/bag to it like the zip on day bags/rucksacks you can find in non photography shops. I don't know if these are available with camera sections? But it would make transporting my gear between locations much easier as we will be on the move every few days! I also want the camera bag to look discreet not scream "I have expensive cameras in here - come help yourselves!"
And I also like camera bags which have compartments for lenses etc in the bottom of the bag with a compartment for other stuff in the top as I will be out for the day not just for a photography shoot as my photos tend to be a documentation of my travels as opposed to planned shoots! The gear it will need to carry day-to-day is 1 small-medium sized camera body with 4 lenses (all quite compact no huge telephoto lenses) a gorilla pod and several screw on filters.

So to sum up I'm after a bag which can be attached to a rucksack, looks discreet and can hold non photography items too! Anyone know of such a bag or do i need to think of an alternative?

Thank you!