I've done a ton of Lease/Purchases since I also property manage. Let me know if I can help you.
They are not what you expect, hope my comments keep you from getting hurt, good luck,
Take the time to understand completely what you are getting into. Do not enter into any agreement with out checking out your landlord completely and having an attorney review and add protection for you in the contract.
Banks aren't in the business of renting houses out. And you wouldn't want a bank as your landlord in any case.
If you want to do a lease-option, that's fine. (I'm a big advocate of them. Others here on Trulia are less enthusiastic. Just know what you're getting into; read all sides of the discussion.)
However, find an individual owner willing to do a lease-option. There are plenty around. And make sure you have a lawyer review the agreement. There are various protections you'd want included.
Here's a link to a blog I wrote on how to find lease-options: http://bit.ly/findaleaseoption
Hope that helps.
All the best,
Chapman Hall Realtors