Well, I thought I would throw in some other ideas I've come across for knife storage, in case anyone is reading this thread for ideas on how to store their collection. Storage is always a combo of space, security, accessibility and exposure. How much room do you have, how much security do you need, how easily accessible do you want the knives to be, and how exposed (to light, dust, for show) do you want them to be. At the higher end of the spectrum, other parameters should be considered, like humidity, contact materials, air-flow, etc. Busse knives are so tough though that one need not worry too much about these things with them. For high-end knives, a big heavy gun safe is a good idea. For low-end stuff, here are some other ideas:
1) A locking metal storage cabinet from one of the big-box office stores. Order a second set of extra shelves for it, so you're not wasting vertical space inside the cabinet. Has the advantage of a being made of a stable material, no smell or off-gassing, relatively light in weight, good-looking and spacious.
2) Have a local woodworker build a custom cabinet with glass doors and less space between shelves than the typical curio cabinet. Line with cotton sheets or use display cases inside of it. Has the downside of being heavy, requires cure-time, and you'll need to decide the trade off between off-gassing polyurethane or raw wood that attracts moisture.
3) Check your local office furniture surplus place for metal flat file cabinets, like the ones architects and decorators use. They take up alot of room, but offer alot of space in those wide, deep drawers, which are just the right height for knives, not like regular dresser drawers.
4) Bisley makes some little file cabinets with many small drawers. They are pretty affordable, and you can buy separate plastic inserts to divide the inside of the drawers even further. Their standard 4-way plastic dividing tray is perfect for folders.
5) You can use a standard metal office cabinet, curio, or other type if cabinet, and gain lots more storage space, by adding the clear plastic holding trays the Container Store sells. I don't mean the ones made for sheets of paper. They have deeper/taller ones that are also less wide, that seem to be the perfect "cubby" size for a knife and its box or sheath, and are also long enough to accommodate large fixed blades. They are stackable, so by stacking them, and putting them alongside one another, you can fill up the vertical space between shelves while giving each knife and box its own cubicle. This kind of plastic is not totally stable, so you'll sacrifice a 100% pure environment, but it's a hard plastic that is mostly stable, and the fumes in contributes to your storage micro-climate are barely noticeable.
There are lots of other solutions, like hanging cloth shoe organizers in closets, building a shelf-rack system inside a closet, and trying your local "raw wood" furniture place for cheap units with many short drawers, etc.
Post other ideas if you have 'em. I always enjoy learning about other storage ideas I haven't thought of.