IWBNI the calendar view (well the calendar) could subscribe to a calendar (e.g. a holiday calendar). Two ways that would be useful:
- Just display entries at the top of the appropriate column
- Make events in the calendar exclude working time.
The first would be good for (e.g.) the list of holidays, since not all public holidays are work holidays (especially if you subscribe to several, like your customers' countries' holiday calendars too) -- you can manually notice that. The second is good for things like company calendars (with actual holidays, all-handses and the like.
They'd be handy in the timeline view too but I don't know how to do it without making things cluttered.