How does one rent an apartment with poor credit?

The person in question is self-employed (business owner), has enough money to pay 6 months rent up front, but he has really bad credit. It seems like in this area noone cares how much money he has in the bank, but they all run credit checks (Nothern CA). It takes a long time to re-establish good credit, but he needs a place to live now, not 6 months from now. What can he do?