capture mousewheel scrolling over a hotspot

Is it possible to capture (prevent from impacting main output) and trigger (do something else) on mousewheel events?

Not at present, although it is probably something that could be usefully added. What do you want to do with it? Scroll a chat window? Zoom into a map?

Yes and yes.

I didn't find a completely complete chat window plugin around here, so I've been working on making one starting from what was available and moving toward awesome.
http://code.google.com/p/aardwolfclientpackage/source/browse/#svn/trunk
The one thing that will be missing is scrolling with the wheel.

I suspect I'll want to add scroll-zooming to the world mapper too.