A remark on another forum gave me an idea.
Who else would like to be able to place a "guest stable marker" - basically a space for a mount - in their home for a vistor's mount to occupy while they're there? You can place an instance of any mount you own in your stables (assuming the home has one), but it would be nice to leave room for guests to stable theirs, too. Placing an empty marker (visible only in edit) would allot a space for one mount, filled on a first come, first served basis when guests arrive.
I'm not sure what type of furnishing that would need to be for slot count purposes, but I wouldn't think more than a few would get used at any one home.