So I went to the "Earth Day at Dallas' event to specifically research the solar energy and three different companies were represented. I had time to talk to only one of them - 1SolarTech.
They provide a 'Pre-paid' lease option, in which you pay all of costs upfront but the product is leased to you. You don't own it. The main advantage of doing this is that they own all of the maintenance and repair throughout the leasing period. I don't recall what the leasing period was, but I will get back with more details. I gave my address and my 12 month usage numbers for them to research and get back to me.
I will get back to you as I hear from those guys. But rough calculations make it seem the ROI is close to 15+ years. Stay tuned.