Be honest with your landlord from the beginning. (we're not all SOB POS's). If you think this information is important, then let them know when you submit your application that you have a co-signer in the wings. If a co-signer isn't needed, a landlord isn't going to ask for it or take advantage. There's no gain in adding a co-signer when not necessary, so nothing to take advantage of.
And to touch on Tom's comment - if your history with landlords leads you to believe that the majority of them are SOB POS's, then look no further at yourself. You are 1/2 of every landlord/tenant relationship that you've ever been in. We deal with a LOT of people on a daily basis, and I can attest - if you start the relationship by being a SOB POS yourself, you're going to receive it back from your landlord.