In the terms implied in this post, I am just one step away from being an extreme libertarian. Do you smoke and drink? I'll drink a toast to your health as I enjoy my cigar. Want to jump off a cliff? Try to hit some public property and spare a private landowner the cost of cleaning the splat. Not evacuating from New Orleans as Hurricane Katrina closes in? If you are not in the Superdome, I'll put your name in for a Darwin Award.
I'm not really sure if I don't qualify as an extreme libertarian, because in the example he gives, I my rational for being OK with compulsory quarantining comes from an important libertarian principle. I phrase it as: Go ahead and kill yourself, but thou shalt not take others with you. Jumping off a cliff: OK; Jumping in front of a bus: not OK. If a person is ignoring a quarantive order, then he is putting many others at risk, and that is just not tolerable.