@vexe,
Cool that you've made your own. I'm definitely interested to check it out when you are finished.
But really, not having payload support in an event system is really missing the point. Leaving this functionality out based on the assumption that "who will supply the arguments to the delegate" is forcing us into a very limited view of how to solve problems using the event system. An API like NGUI must realize that the set of problems and solutions that are required are much greater than any one person can ever anticipate. It's the job of the API to provide enough flexibility and not to dictate how the solutions should come.
Every Event system I've seen has support for Payloads. This is oversight that has to be fixed by NGUI itself so that we do not need to re-apply our own work around with each new update - and these NGUI updates are coming fast. Let's hope that the next update has this fix.
Cheers.