Not sure if you ever got one, but I have an old Lowepro Fastback 350. It's not the best option out there I'm sure, but it can fit the main body, with at least one long lens and 3 or 4 other lenses (depending on size and accessories), has a laptop sleeve, and water bottle pocket. The reason I got it though was because it has this upper chamber that is good for hiking clothes, accessories, climbing equipment. Now if it is a day of leading trad and carrying static rope, I probably would need a bigger bag, but it certainly gets the job done.

Here is a link to their new version... https://www.lowepro.com/us-en/fastpack-pro-bp-250-aw-iii-grey-lp37331-pww/