The first question that comes to mind is "why would a buyer lease option?" It's probably a stretch to advise buyers that that is a prudent move. More often the home owner (landlord) receives a heck of a lot more benefit than the tenant/leasee. Generally, a property is rented at an above market rate with the premium being applied to downpayment if the purchase option is excercised. Statistically few tenants move forward with purchase and, therefore, forfeit any rent premium. Seller/owner just made out great.
Consider the market swing we're in. Which way are prices headed? Many lease option agreements lock in today's price. 12 months later you could potentially purchase a similar property for significantly less. Again, seller locks in today's price and hedges himself against further property value decrease if sale goes through. Also, keep in mind that rarely are Realtors involved and that's big $$ in the seller's pocket. When gathering comparable sales data from surrounding properties keep in mind that 99% of these include a 5-6% Realtor commission (I don't exactly know what numbers are for your area). If there's no agent involved look at comps minus 5-6% as market value. Most buyers/sellers overlook this!!
Attorneys or Realtors typically write up these agreements. Check the local BBB, real estate agency, or state bar is my suggestion... if there's really a benefit to you going through with this. Best of luck whichever direction you choose!