9/24 Update - A new iClock is on the way for Mac OS 10.12. We are trying to iron out some final details.
"Clock Pro from Plum Amazing is truly 'the Essential Mac Menubar Clock' which they advertise. It is described as “a time hub which replaces the Mac OS X clock with many more useful menus, options and applications that everyone can use in day to day life. That really is a very significant understatement. It is truly amazing all of the features included in the program, many of which I didn’t even know that I needed, but now won’t live without! My daily Mac use is now much improved with this addition, well worth this small investment in productivity."
- Tom Piper, AppleJac - 3/25/15