First, I am not a lawyer.
It seems that BHO was not the POTUS until Roberts swore him in. Remember, they did it twice to make sure.
If Roberts swore BHO in on false pretenses, could Roberts rescind or invalidate the swearing in?
I know one cannot transfer title of stolen goods.
I think it's more basic than that; Roberts needn't do anything. If in fact, Obama is Constitutionally ineligible to hold the office of POTUS, he has technically never been POTUS regardless of how many times he was sworn in. This is at the core of LTC Lakin's refusal...he is not going to follow the order of a person who's viability to issue the order is in question. The fact that 99.99% of the Executive Branch has deferred to his ascendancy as legitimate may make Obama the de facto President, but it does not make him the de jure President.