I am SO interested in the solar movement and am hoping to transition my career into the solar industry (from commercial banking).
As for financing, if you have home equity and good credit/income you could definitely get a home equity credit line or term loan to finance the purchase. Not sure how this type of bank financing would compare with the targeted solar financing out there. I check out various solar companies and most seem to offer some sort of financing, usually secured by a deed against the home.
Kudos for taking a step toward making the earth a cleaner place!