You mean to say that sumbuddy wants to rent a house but don't got no job but has the cash necessary to pay the rent, right?
And you are asking for a believable suggestion about what lie to tell a reasonably intelligent landlord to give the landlord some peace of mind that the rent is going to get paid, right?
Tell them you are an artist. Go to a second hand store and buy a shitload of cheapo impressionist art - pottery, jewelry, photos of Lady gaga .. whatever - attach price tags to each piece ($900 - $2300) and then show the landlord "your work" and tell the landlord that you "usually sell about one piece per week". Haave a telephone number for an accomplice ("an art gallery") ready to give the landlord as a reference.
Need more ideas for plausible lies???? Just let me know - I got tons of 'em