Wow, Billdo, I got the same e-mail! We must both be impotent. I mean important. I’m sure they’re very valuable degrees. Worth at least, oh, $1.75 in terms of the paper, ink and mailer.
… and they told you this without laughing hysterically? Really?
I can’t think of anyone I know who went from BS/BA to PhD in under 5 years. I got my Masters quickly, relative to most people at UVa, and it took me about a year, but I didn’t start it until my second summer in grad school. The first two years were for taking classes.
I did take an extra year to get my PhD (due to Hubble’s flawed mirror and an addiction to Netrek) and it took a little over 4 years. My total time was:
Entered grad school with BS: fall of 1987
Left grad school with PhD: summer 1994
Which is a little long of typical, but not by much.
Well, their website says:
The website of another school I applied to says this:
Well, I guess your words worry me, but not too much. The longer I can drag this out, the happier I’ll be. 
In physics, “all but dissertation” is otherwise known as “master’s degree”. The Comprehensive Exam, orals, and almost all of the coursework are done for the M.S. level. Count on somewhere in the neighborhood of two to three years to go from B.S. to M.S.
For the Ph.D., you might need one or two classes, but the rest is all thesis (and other research). How long it takes will depend largely on whether you’re an experimentalist or a theorist. An experimentalist can generally go from M.S. to Ph.D. in a couple of years: You do your experiment, and if you get the results you expect, you write a thesis saying “We got the results we expected”. If you don’t get the results you expect, you write a thesis saying “We didn’t get the results we expected”. Of course, it’s still possible to get setbacks from things like equipment failures.
For a theorist, it’s less predictable. A theorist might spend ten years between master’s and doctorate chasing down wild geese, or he might breeze through in a year. Usually, of course, it’s somewhere in between, but there’s a large spread. All theoretical physicists secretly (or not so secretly) envy de Broglie, who managed to write a three page thesis and get away with it.