I've had this one for many years:
Targus.
I'm not sure it's that size and it's not exactly the one as pictures, but as I said, I bought it five years ago. My 13 inch MacBook fit perfect and the same goes for my 13 inch MacBook Air. Inside, it has an added velcro belt to put in the computer more securely. You can put your iPad on top of your computer as well, it's certainly deep enough. The pouch has a few separations for cables. I sometimes put a book there as well as the cables, or my iPad. I'm very happy with it.