UPDATE: This post at American Creation blog is a nice summary of Calvinist views of Romans 13. Gregg Frazer, Dean of The Master’s University and historian of the founding era wrote to address Calvin’s perspective on political rebellion. In short, without some governmental sanction for resistance (e.g., impeachment), Christians should not rebel. However, impeachment and removal is built in to the Constitution and therefore legitimate. Christians should not appeal to Romans 13 as a reason to oppose impeachment.
My position is that Dr. Frazer's case is an airtight interpretation of Romans 13; but there is more than one way to skin a cat.