Utterly Mad

Here's a more sane gun:

Oh yes, the pepperbox. The very peak of sanity. You never know if it's going to fire one barrel, some of the barrels, or all of the barrels with a single pull of the trigger. Truly the most sane of the "wild card" pistols.

Then of course there is the Mateba 6 unica autorevolver. A gun that fires from the bottom of the cylinder instead of the top and is very close to something you would see in borderlands, except with wood instead of neon painted metal. Warning, big image.

Spoiler (hover to show)

OR if you are in the market for a more "quake" like weapon, you could always get the DP-12 double barreled shotgun.

And yes, that is a real shotgun, and yes, it comes in a 4 barrel variety as well.
OR OR, if you are short on cash, you can get an "Obrez" mosin nagant.

Of course, I would opt for an unbutchered mosin myself.