A couple of weekends ago, wife was away so I decided to re-organize one of my safes. I was about to go and buy some materials to build a vertical pistol rack out of wood (I tried the metal ones but they're too narrow to store pistols with trigger locks attached). Before I bought the materials, I zipped by the storage section of my local Lowe's and found a shoe storage shelf with 15 little cubbies - each perfectly sized for a trigger-locked pistol and a mag or two. So now, 15 of my handguns each have their own spot (I'll try to post a pic later). The only one that didn't fit was one of my old Russian free pistols (barrel length and monster grips).
I did have to build the shelf inside the safe to make it fit - a minor pain, but it worked well.
If I hadn't gone this route, Lowe's also sold some other near hanging shelves that would have worked.