This is something that is already supported in Google Calendar. Adding additional columns in the calendar week/day view that show additional time zones. The days should still correspond to the default time zone (either defined by the user, or set automatically to match the system’s), but seeing more time zones will help planning travel, meetings etc.
It is already there in version 11.
Great! Can’t wait to upgrade once it becomes stable 
Any estimates on when that will happen?
We are very close to a release date. It should be 1-2 weeks away from now.