At the top of the gaming laptop pantheon are full-size "luggable" desktop replacement laptops. While these are still laptops in the strictest sense, they are essentially made to be portable desktops rather than lap computers or even a machine meant to be used away from mains power for an extended period of time. This allows them to use component choices you couldn't do in proper laptops, improving performance at the cost of weight.
Dell Home, via its Member Purchase Program, offers its Dell 15.6" Laptop Gaming Backpack in Black/Red for $28.49 with free shipping. That's tied with our expired mention from four days ago as the lowest price we've seen for this bag. (It's the best deal we could find now by $20.) It accommodates laptops with up to 15.6" screens and features a shock-absorbent EVA molded front shield, adjustable shoulder straps, and a deployable rain cover.