I have a camera/computer satchel by Ona Bags - the Brixton, which handles a Macbook Pro or basically any 14" laptop just fine (they say 13", but my new Asus G14 fits). I bought mine in 2013 and used it pretty much constantly; it's been around the world and seen plenty of abuse. There are two flaws in the canvas now; one on the back where it rubbed against my pocket knife's clip, and one where there's a seam that folds. Neither are functional issues and are barely noticeable. The strap and hardware have held up perfectly, and the waxed canvas has aged really well.

That said, my recommendation is for the full leather version for a BIFL bag. I may upgrade to that in the future, but it likely won't be because the current bag failed.

They have larger versions, too - the Astoria for up to 15", or you might be able to find the Union Street which is a discontinued model online or second hand. I wouldn't hestiate to buy one of these bags second hand as long as you get good pictures to make sure seams, buckles, etc. are all in good shape. They're proud of these things and the price reflects that, but considering mine has been going strong for a decade, I've spent like $35 a year on it.