Many thanks to a comment from Pej. It turns out we have a fifth Dr. Doom. Peter Schiff.
In an August 2006 interview Schiff generated much controversy when he repeated his long-held investment thesis: "The United States economy is like the Titanic and I am here with the lifeboat trying to get people to leave the ship ...I see a real financial crisis coming for the United States." On May 16, 2006 in debate on Fox News, Schiff accurately forecast that the U.S. housing market was a bubble that would soon burst. On December 13, 2007 in a Bloomberg interview on the show Open Exchange, Schiff further added that he felt that the crisis would extend to the credit card lending industry.
Thus Peter Schiff appears to have indeed laid claim to the alias Dr. Doom, in addition to Nouriel Roubini, Marc Faber, Stephen Roach, and Henry Kaufman. Though from a preliminary read of his views, his gloom and doom seems to have been de rigeur, in terms of a housing bust and excessive consumer credit. I feel a lot of people sort of acknowledged that US housing prices were quite high and that growth in consumer debt would have its limit. Twin deficits was another bandied about problem on the radar. But the real suprise was when US housing weakness caused damage in all sorts of seemingly random, far flung places, knocking unexpected companies into insolvency and freezing up credit markets as the entire financial system, globally, lost confidence in itself. Who thought that major US financial giants would be blown to bits within months by the eventual fall in housing? Anyhow, we now have five known Dr. Dooms.