Why not try to buy instead?
Any contract worth it's grain of salt is going to require you to pay a substantial amount of money down...maybe you should revisit the possibility of owning instead of renting.

Email me with details of your plans, and I can possibly lead you in the direction of owning a home the traditional way instead of lease to own options...the lease to own option, much like a Bond for Deed has become an issue for sellers who still have a mortgage on the subject property.

You can contact a realtor in your area to help you. I am sure there will be some that reply to your question.
There are homes listed on the MLS that indicate these type financing options.