A major point that underlies my thinking above is that we've talked a lot about automating the display, form building, and other UI aspects of objects so that arbitrary packages can gobble up and attach objects of any type and incorporate their display and form input into their own pages.
The calendar's an obvious example of a package that could greatly benefit from such an approach, but it's not the only one. A solution that works for calendar only falls short of what we want to accomplish.
Of course, there is that nagging issue of available resources to implement any scheme :)
