Do you think they can get a Constitutional Amendment approved by Dec 15 2008?
They don’t need to. Any court with authority to declare President-elect Obama ineligible (either ultimately, i.e. SCOTUS, or pending appeal, i.e. a lower federal court) would simultaneously stay implementation of the ruling until SCOTUS ruled on a proposal for how to proceed with electing a new President. Getting such a proposal drafted and approved would take longer than getting a Consitutional amendment passed, and in all likelihood the proposal would contain a delay feature to allow for a fast-tracked Constitutional amendment process to be carried out first, with the procedure for selecting a new President only to be used if the amendment failed.
The only possibility involving even temporary removal of President-elect Obama would be to place Biden in the office of President on a temporary basis, until the Consitutional amendment process (which Biden would fully support) was carried out. Biden would take orders from Obama during this period, and the only difference from having Obama in office would be extreme political instability, crashing financial markets, and gleeful Islamic terrorists taking full advantage of the chaos.