I know it's a little late, but I have been pondering the same thing, and searching the internet for ideas. Although what I was really looking for was validation of my own idea.
I have a cheap alarm clock that I bought for exactly this purpose. It operates from a 1.5V AA cell, and has a Lavet mechanism internally. My idea is to set the alarm to 12:00 and detect the alarm switch activation (which you can hear clicking on when you move the hands to 12:00).
So, once I disconnect the driver board from the coil and control the hands with an Arduino, I can detect 12:00 by monitoring the alarm switch. Therefore I know the hands are in a known position.
Probably cheaper and easier to find than the clock modules with optical sensors, albeit slightly less accurate at pinpointing 12:00 precisely.