"anyone know if it could in theory be done?"
Just create promises to pay on demand, maybe called these Bitcoin Reserve Notes, and then create institutions that recognise all gains immediately while hiding losses for years. What to call these? Magic the Gathering is already taken, I hear, maybe Biankts?
But I wonder if it can push the price of Bitcoin down like deriveratives do to Gold. I mean if the price of real Bitcoin on the excnages are one price and the eft is vastly different then no one will take it seriously. With Gold there is enough manipulation on the offical excnages like the Comex that no one realy can determine real market value.