I have been using this case logic backpack for about a year and a half and it has a laptop pouch in the back. It fits 2 of my DSLRs, a few lenses, and my audio equipment.

4:50 EST = Case Logic SLRC-206 SLR Camera and 15.4-Inch Laptop Backpack (Black)

https://www.amazon.com/gp/product/B002DW99H8

I use it with the stock 4k and there's room to spare. The only downside is it can get top heavy if your camera body is the heaviest thing in your bag. I learned about it from this: https://www.youtube.com/watch?v=DHt12BmewPU