I think the 25th amendment (which primarily deals with the incapacitation of the Pres) would kick in here as well:
Amendment XXV
Section 1. In case of the removal of the President from office or of his death or resignation, the Vice President shall become President.
Section 2. Whenever there is a vacancy in the office of the Vice President, the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress.
Section 3. Whenever the President transmits to the President pro tempore of the Senate and the Speaker of the House of Representatives his written declaration that he is unable to discharge the powers and duties of his office, and until he transmits to them a written declaration to the contrary, such powers and duties shall be discharged by the Vice President as Acting President.
Section 4. Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.
http://www.law.cornell.edu/constitut...ndmentxxv.html
Confirmation by both the House and Senate would make for an interesting scenario, particularly if we were to extend the scenario further with the thought that Bush could nominate someone like say, Condi Rice?
But it aint gonna happen. Kucinich has ZERO co-sponsors for his impeachment resolution.