This idea comes up every so often, you're hardly the first. There's a good reason why you don't see many DIY places, and it's what everyone here has already mentioned. One serious accident could wipe you out without good coverage (or even with it, given the potential lawsuit award). Not to mention the landlord might decline to rent their property for this type of use.
Most likely the insurance quote will stop you in your tracks, and that's if your agent is even willing to offer it to you. But good luck trying, let us know how it goes.