All this talk about starting from engine bay reminds me something I
had in mind for a long time:

Is there a contact anywhere in the gearbox that one could use to tell
the vehicle is in gear or not?  A lot of newer cars have the switch at
the clucth pedal to make sure the vehicle does not start & go when you
crank the starter.

The kind of unfortunate incident this could be used to prevent has
happened to yours truly a few times :-(

Tanks,
Cetin