Lewis, I have twenty bikes on display in a room over our garage. This room is totally devoted to my bikes and other collectibles. I mounted brackets on the wall, about two feet from the floor that hold the wheel secure enough to keep the bikes in an upright position, but allow me to pull one out for show or preparing to ride. I alternate the position of every other bike to optimize the space (every other bike has the rear wheel to the wall). The only bike I have that is wall mounted is a Cinelli that I thought deserved a "special" place. I also have another eight bikes that occupy the second half of our "two car" garage. These are simply mounted on stands purchased from Lowe's. These hold two bikes apiece and are neat because they can be added to later on. Five unbuilt frames also hang on the garage wall from bike hooks along with wheels, cranks, brakesets, and other bike stuff. As this doubles as my workshop, I still have room for more bikes.
I hope this helps, but I guess we all soon reach a point where we either have to thin out our collection or stop collecting. I refuse to be a "hoarder" and just pack stuff away in boxes or such. Collectibles, especially vintage bikes, should be displayed. It also helps to have an understanding wife (or roomate) as I've kept one or two bikes in the family room until I could reorganize.
Fred Durrette
Summerville, SC