I dealt with a similar issue on my website, www.lakotawestbands.org (check the calendar page). I have a straight forward monthly calendar showing on that page, but I also have a link that says "Create a Custom Calendar". In THAT view, the calendar displays "Mixed-In" Calendars and the search field.
I did this by creating another top-level calendar and displaying all the same sub-calendars from my main calendar. To do this easily, I have NO events in my top level calendars...only in the sub calendars. By the way, the displayed name that you give those two top level calendars can be identical. And since they share the same sub-calendars, a change in one sub-calendar shows up in both top-level calendars.
Okay I think I've confused myself. Hope this helps a little,