Correct. Pay-per-view already exists and it would only be an extension of it. If the cable company provided a simple web site or phone menu system you could pick once a month or so what channels you wanted for that month and that would take care of your viewing choice and billing.
No, what I would like is for the whole cable thing to be like a taxi meter -- it doesn't start charging until you turn on the cable system (as opposed to just turning on the TV). That way you only pay for which channels you watch, and only for how long you watch that particular channel. Therefore, no need to pay $XX a month for the, say, Turner Movie Classics Channel, when there are only 3 or 4 movies in the month that you want to watch.
(sigh) 'Course I wish I had a pony too...