In New York City real estate, there are few titles more thankless than guarantor. People who do not make enough to afford their paycheck-devouring rents must find a well-paid relative, a benevolent family friend or perhaps a kidnapped and hypnotized multimillionaire to supply personal financial information and assume responsibility for their entire lease. Rachel Wagner, Emily Coit and Taylor Jewell, recent college graduates and childhood friends from Portland, Ore., discovered that finding such a guardian angel was almost as difficult as finding an apartment.