If only I had this problem. I consider myself lucky to have one bike right now. It's been a saga just getting to the point I am now where that one bike is going to finally be a bike of good quality and not just a BSO. I could maybe make room to store one more bike in my apt. building's basement/utility room, but I doubt I'd be able to convince my wife that it's needed.
FWIW, I do dream sometimes. If I were to go N+1, I think it'd be a 1x_ or a SS setup on an old Peugeot frame...