Another thing you can do that has worked for me in teh past was to write a resume for your pets. One for each. Put their picture at the top of it and then write the resume as if they are applying for a job. Make it fun and enjoyable to read. Have some of their good points as being clean, well trained and so on. I also like to list tricks they can do. At the bottom have a list of references that can be phoned to not only back up the resume and how the pets behave but also how well you care for them.

I know it sounds silly but it has always worked. It gets your foot in the door. Puts a smile on teh landlords face and is honest. Many places I stayed in did not allow pets but this always seemed to change the landlords mind. Either way references for pets is a very good idea. Just an idea for you that worked for me.
Nicole