As a matter of fact, I have a simple one in place that works very well
for web-traffic. In a MySQL database, 10,000 page views takes aprox 3MB
(we only record page views, not hits). Periodically, we normalize this
so that it takes much less space than than.
Once done, it's very easy to create some real simple reports for
bandwidth, page-views in a period of time, etc.
We have it updating at approx 15 minute intervals, so that our reports
are near-time. I'll bet you could knock out a solution workable for you
in a day or two.