At the OP- As a kid my dad always kept our guns in a large gun cabinet at the end of the hall. Nice way to display the guns, somewhat of a status symbol IMO. I dont know of anyone who does that now. If your not concerned about fire rating then make one and use 3/8" lexan (bullet proof glass) for the glass with some bracing. Heavy wood or steel reinforced doors would be a nice touch. If you need some specialty locks, hinges, hardware check with mcmaster.com I order industrial products from them all the time. If they dont have it, it probably doesnt exist. Prices are high on some stuff like lexan panels.
Concentrated power is not rendered harmless by the good intentions of those who create it.