Hey. Not to repeat myself, but I do think you've gotten some of the dynamics of the left on health care a bit wrong.
The true single-payer-or-bust rump of the left is very tiny: Physicians for a National Health Plan, and their fellow travelers. And they *do not* play ball with the rest of the universal-health-care crowd (Families USA, HCAN, etc.). In fact, David Himmelstein of PNHP just called Howard Dean a "liar" last week.
And to be fair, Dean probably was a little squishy on the facts.
Even the public option magic-wanders at Kos are not really single-payer fundamentalists. Here in MA, Health Care For All is *definitely* not that -- which, of course, enrages PNHP et al.
You may think a public option will inevitably lead to single-payer; Michael Moore may agree; but I'm not at all sure. And I suspect the vast majority of UHC advocates are more agnostic and pragmatic about means and methods -- even while feeling passionate about the public option, and even while wanting to deliver a big, well-deserved middle finger to the insurance industry.
All this is to say that public-option-mania is *not* equivalent to single-payer mania, the latter of which is decidedly a boutique phenomena. I might suggest taking advocates at their word, since the disagreements are out in the open.