Michael, I think this would be an easier feature to employ by building the capability to view the reverse sides when in the export to poly's dialog.
It's really most useful at that stage of modeling, where it makes the most sense.

If anyone is up to the task, I bet there's a way to write a script that could draw little lines, perpendicular from the surface normal.
They could be colored and assigned a name, so that they can be deleted later.