Oliver Platt as President Herbert Hoover
Sela Ward as First Lady Lou Henry Hoover
Richard Riehle as Vice President Charles Curtis
Jared Padalecki as Herbert Hoover, Jr.
Max von Sydow as Treasury Secretary Andrew Mellon
Kevin Spacey as Successor Franklin Roosevelt
Voice those re-casts in the comments! (Or, you know, approve of my choices - that'll work too.)