I think the rent-to-own idea is pretty clever but how would you structure the control of the domain--DNS, etc. I would be reluctant to build a business around a domain which an unscrupulous domain "land-lord" could then redirect to a different site at his whim. I understand that there would be a contract to prevent this sort of thing but while the issue is in courts, your business just died.
>> I would be reluctant to build a business around a domain which an unscrupulous domain "land-lord" could then redirect to a different site at his whim.
That was my first thought when reading that option. You'd definitely need some legal coverage if you decide to enter into that kind of agreement.