To answer your basic question...Are there really women who are Multi-Orgasmic....Yes there most certainly are.
I have been fortunate to have known a few both in the Civie and Hobby world. Most of these women could get to double digit O's over the course of a couple of hours before they ran out of gas or the sensitivity overload is too much. They could get off from both Clitoral and Vaginal stimulation.
In regards to your thought that a woman can't keep going all day.....Some actually can and I know a couple of them.
I am incredibly fortunate to have found a woman that does not have an Off Switch... She can have orgasms all day and night long and never gets too sensitive.....Oral, Vaginal, Anal, Fingers, Toys etc....she can climax from all of them and still want more!! And I love every O she has!!!

She absoultely wears me (and the rechargable vibe) out!!
On the other end of the spectrum I have been with women who rarely if ever climax. My college girlfriend could only have one orgasm and that was after an hour of intense DATY....That was when I discovered Vibrators!!
I have been with a few providers that just don't orgasm very often....they still enjoy sex but the Big O is usually not in the cards..
Like with men and the number of Pop's we can have in an Hour or Day the number varies wildly and changes with age. So there is no definative answer to your question....everyone is unique in how she/he responds and that is what makes it all so interesting.
Just the observations of a long term hobbyist.
Quote:
Posted By: ctcaman
In reading reviews there are ladies that claim they cum all the time either via oral or vaginal stimulation or that's what we read. In my experience with civies there is only so much stimulation a clit can take in a day. PLus there aren't that many ladies that can cum via intercourse. Add to that we probably aren't the only person seen that day. So is the acting that good or the providers just that horny? Because from my normal session I am thinking I'm done for the day and I would think she would be too. How many times can a lady cum in a day? In the showtime series about providers one of her rules was to never have an orgasm. So is it real or is it memorex?