Bit of an offshoot, but since the question of where the furnishings would stored came up - perhaps they could implement a Furniture Salvager NPC. Furniture is bound to your character once it's placed anyway, so there wouldn't be much to lose by just having this as an option.

The main issue that they would need to work with is the sharing work-around via the FC chest. Perhaps they could have two handling options for furniture - 1) Initial furniture purchase/use still works the same - can still store in Retainers, share in FC chest and sell for gil and 2) Manually turn item in to the Furniture Salvager - this lets you repurchase the item whenever you want, but it cannot be sold to NPCs or stored (to prevent sharing).

Just spit-balling here, so there may be more issues with that. I'm sure it's never going to happen, but I can dream! I currently have a retainer full of furniture due to being between rooms and waiting on an apartment to open up on Balmung (HAH!).