I like the ones you hang on the inside of a vault door, but I've also been considering something like this to organize the vault;
Cabela's: Versatile Rack Safe Handgun Rack
Cabela's: Hyskore® Modular 3-Gun Pistol Rack
You can buy one line this:
Cabela's: Versatile Rack Safe Handgun Rack
from Bradis, that is where I got mine.