I came up with the idea, my dad implemented it in steel for us this year.
I used the tuffy console to bolt it to, but if I had a stock console, I would have used the seat belt mounting bolts.
Just used square tubing just larger than diameter of gun butts, put piece of metal across the bottom, semi-soft foam over that, vertical pole in between two of the butt "sockets" and then an arm for either gun barrel above where the forend of the gun ends. The arm has one 3/4 circle of PVC (one for each gun) riveted to it, with foam pipe insulation glued inside it, to not scratch the gun. Slit in the insulation allows the gun to be pressed into the arm, and a strap of velcro runs around either one or both guns, to keep them tight against the pole.
Pretty complex, but I hated the way guns got in the way of the back seat when I had passengers, and they were always bouncing around. This way I didn't have to screw the body up at all, they are out of the way, and with almost two weeks of rough hunting roads, not once did a gun find its way out of the rack. I should take a picture of it, it works awesome.
Probably more complex sounding than most are looking for, but it works, and isn't too hard to make if you've got some metal laying around.