Odd, Timbuk2 doesn't make a laptop bag that fits these dimensions.
"I spent maybe 2 hours working on it and it works perfectly!"
As long as it works perfectly for longer than two hours, I think you're in the clear.
No intelligence allowed.
Okay you guys, I got this. We buy a bunch of mattresses. Yeah, mattresses. We texturize and paint them, then sell them to 2nd-rate New Jersey contractors. For literally hundreds of dollars. What could go wrong?