Rent to Own or Lease Option deals are pretty rare and must be drawn up by an attorney. There are no standard lease-option contracts in Texas. This kind of agreement is fraught with risk and liability and I don't know a REALTOR who will work one of these.
The cleanest way to accomplish what you want is to simply find a house that is available for lease that the owner would consider selling sometimes in the future. You can just ask them if they think they would consider selling at some point in the future. Some never intend to sell, but want to keep the property in their family as an asset. Others are open to it at some point and some may like the idea that you might want to buy it in a year. Go ahead and lease it and after your lease if up or in one or two years, then talk to the landlord about the possibility of buying it and whether he might give you a break on price since you've leased it or whether he might owner-finance it. If it looks like the owner is agreeable, then talk to your REALTOR about the next steps to take.
Bottom line, consider the process as 2 separate transactions. LEASE the house you want to live in for the next year or two. Then enlist the help of a trusted REALTOR to help you buy the same house or to help you find another home to BUY. What generally happens is that after a year or two in a leased home, tenants usually want to have the huge range of choices out there when they are really ready to buy. You can look at different locations, different amenities, school districts, proximity to work and play, etc. Tenants very rarely buy the house they lease.
I hope this answers your question, but if can help you further, please contact me as shown below:
Coldwell Banker APEX REALTORS