From ABC:

New unreleased e-mails from top administration officials show the idea of firing all 93 U.S. attorneys was raised by White House adviser Karl Rove in early January 2005, indicating Rove was more involved in the plan than previously acknowledged by the White House....
White House press secretary Tony Snow told reporters Tuesday that Miers had suggesting firing all 93 and that it was "her idea only." Snow said Miers' idea was quickly rejected by the Department of Justice.

However, Miers was Bush's staff secretary at that time in January 2005. She did not become White House counsel for another month, after Gonzales left to become attorney general.

The latest e-mails show that Gonzales and Rove both were involved in the discussion, and neither rejected it out of hand.