You sure about your offer again? 
Are you sure about anything that spews from your mouth?
Transfer the title to you, a clause that prevents you from
selling it, we live till the end of the lease period (typically 99
year leasehold), you pay our property tax?
You should place an advert in the papers, see how many people
take up your offer.
This is damn funny!!! Other than your "if you buy something at a
future date at $100, if the price at the future date drops to $50,
you still insist on selling at $100".
Wahahaha.............
Why not just propose transacting the entire proposed deal in the
form of what typically happens in a futures exchange? It'd save you
the transaction costs while still pretty much enabling you to
profit from the mark-to-margin spreads...
