I think I have tried just about every system for storing stamps. Each time I am satisfied with a storage system, I then outgrow it or a new idea comes along. I have been most happy with storing my wood stamps in 11 x 14" acrylic box frames. When you take out the cardboard box inside the frame you are left with a great tray the perfect depth for one layer of stamps. Here you can see part of the tray of my greetings stamps.
And here you can see how nicely they fit inside the tray. I've never gotten around to doing this, but once the tray is filled, you could stamp each image on the paper below so you would always know exactly where the stamp should be replaced after using!
The one problem with this system is having them stacked several trays high. When you want stamps from the lower trays it's inconvenient to have to remove the upper trays.
We moved and downsized about four years ago and when I was dismantling an old bookcase to throw it away, I had one of those lightbulb moments! The upright sides of the bookcase were already drilled with holes approximately two inches apart from top to bottom. Since this was a 12-inch deep bookcase, I decided it would be the right depth for the trays. There was only one stationary shelf, along with the top and bottom, so I had a friend cut them down to a little over 14". Once I reassembled the bookcase, I had a cabinet with an interior width of about 14.25", just enough to slide in the trays over shelf pegs inserted in the pre-drilled holes. Not only is the bookcase much sturdier, it is perfect for 25 stamp trays!
Here is a photo of the inside without the trays. You can see that I used every other hole so there would be space for the trays to slide in. There's also some clearance above the trays so I can slip in clear stamp sets or the occasional extra stamps.
Here you can see a portion of the cabinet. It is actually about six feet tall.
I've seen similar shelves for sale at high prices, so I am very happy to have saved this from the landfill and made it with very little expense! I LOVE this system!