A few additions..
Currently, the sclick event triggers when the click begin, not when it is released (triggered by the uclick event). In opposition, the rclick event triggers when you release the rclick, without an associated urclick of some sort.
I would like to see this changed, so that rclick triggers when you initiate the rclick, just like sclick is, and a new event associated, urclick. In most cases it should not be a problem for older script, only if they in fact specifically require an event for the release of the rclick, which should be rare enough, but they would just edit the event to urclick.
It would be also useful to have a mouse wheel up and down event.