I know someone who I think may be a theonomist, though he supports the separation of church and state (I believe). Would a consistent theonomist oppose the separation of church and state?
I'm not really sure about the Bible, but I do know that the foundational documents of Calvinism call for a civil government entertwined with religion. Make of it what you will.
Political Atheists Blog
More information: He said that abortion isn't murder, but he doesn't think abortion is right for women who have conceived "illegitimate" chilren. That either makes him pro-choice or theonomistic on the issue.