Ask HN: Billing for atomized pricing?

My business partner and I have recently observed that a growing number of web services seem to be moving toward 'atomized' business models instead of a typical flat-rate subscription model.

A simple example of this is Amazon with their cloud solutions: they bill you in extremely small increments depending on your usage.

We are currently considering building what could be described as the Recurly or Chargify for atomized payments as neither of these handle the exact use case I'm talking about.

As many members of HN would be part of the initial target market and will of course have many interesting thoughts, does anyone here have a need for such a product? If so, feel free to leave your email at http://atompay.semblancesystems.com so we can give you updates!

General discussion also welcome: Do you think more SaaS businesses will follow this model in the future? What other solutions have you seen in the wild?