I've long been of the opinion that if you're paying for a rental, it should come with its own "Storage." The easiest way to do this would be to take the exact same script the bank uses with the exact same result, but put a chest in each rental where you can freely swap things out.
For convenience, these can be fairly easily locked to location rather than room -- e.g., all chests in the hotel just register as "stored at Hotel" not "stored in guest suite 2" or whatever. That way they don't have to code fifty separate rooms, and also so that if you lose your rental or switch rooms you can get your items back by asking someone to do it for you. Extra easy would be putting a safe in the lobby of said hotel that does the same thing, but the NPC in question charges a silly amount of money for the service if you don't have an active key. That would both allow people who lost their room to get their stuff back while discouraging people who aren't renting a room from abusing the service.