There is always the option of locking up the actions and pistols in a smaller safe and storing the weapons somewhere else in the house.
Another idea is the safe that fits inside the wall. There are long gun versions and they could be hidden in storage areas behind mirrors ect. They tend to be small but its still an option.
I want a man-cave and I suppose the garage is it for me. The wife can have the house all I use in it is the toilet,computer and bed. (And I could fit all 3 in the damned garage and to hell with the woman!)
It is tempting... if you have a staircase and there is no storage underneath it, look at converting it into a conceled storage area. I used to have a friend who made a cabinet, mirroed the back wall and built in 2 thin safes to the false back. It was alot of work but there is no way someone could have found it. Think of the money you have in weapons and then think of how to hide them from being stolen. Suddenly spending 1k to protect 20 or 40k in weapons is pretty realistic.
Or, I will buy your excess weapons for say...$50.00 and solve the whole issue for ya!