We haven't done so yet. I think the biggest issue you might encounter is the 300' CAT6 distance limitation depending on the number of floors the elevator travels plus the distance to your nearest IDF.
For one elevator I might look at mounting an AP in the top of the shaft (maybe with a panel antenna?) and using the MV12 on a wireless link... But I'm totally thinking out loud here and I have no idea how well that would work.
@lfischer-gcpl I don't think you'd have an issue with the distance limitation then. You'd need to get CAT6 run along with the power/control cables in the shaft and then you'll have CAT6 at the car to mount the camera inside.
Wireless is also another good idea from @jdsilva but isn't available in MV12's firmware just yet.