A "rules-based reporting engine" isn't really a thing, but rather an idea, and there are several references throughout DC of people using iRules to display reporting information. Example:
Heat Maps iRule by Colin
You have to:
-
Capture and store this information somewhere - depending on size, quantity, rate, and value, you could use tables, stats/iStats, remote services, etc.
-
Build an iRule that consumes that data, wherever you've put it, and display it however you need it displayed. In all practicality this isn't done much simply because to use an iRule implies that you're making the data accessible to the outside, but you could definitely create HTML content filled with reporting data, images, you name it. But again, it depends on complexity.
So if it's a lot of data, I'd highly recommend third-party products like Splunk (it's what they do for a living). If it's a little bit of data, stuff it into a table or stat/iStat and collect/display it in an iRule.