Fotis; although never having had "lots" of guns I was up to 30 at one point, I have fewer now. I have three gun lockers in the house, one in my gun room two in the utility room. Smaller lockers or safes in other parts of the house a possible solution? If there is enough height in your gun room you could put those plastic covered hooks for hanging bicycles into the beams and use two to hang rifles. Trigger locks is needed for security. It would look goofy but it would give added storage space.
Good luck finding solution.
