I don't have a house island yet, so maybe this already exists, but here's my idea anyway just in case:
Allow people to dock one of their unused ships off the coast of their home islands. Since many of our ships look really nice but are obsolete once you outlevel them, it'd be a nice way to use them as decorative objects for housing once you don't need them anymore.
I second this suggestion. I like keeping the ships around - love using my raft to do the kill x number of mob quests on the skyways. Raft and main ship are the only ones I need to travel with; but I can not see selling the others to a shop.
I have a house, and you can call up one ship at your dock. I want to see my fleet though and I want others to be able to call up their ships as well so I can see them. There is a single docking port at my house, my friends can't use it. When I go to leave my house I can't leave it by ship, I have to teleport out. I should be given a choice as to where or which main city or world I want to go.