Awesome, @
Diode Dynamics! If the cost for that 4th option is pretty small, I think it'd be totally worth it to add. If it's another $10 or something, probably not worth it.
Would it be another switch, or just an installation option? I imagine if it's just a "leave this disconnected, for OE boomerangs" type thing in installation it would be a pretty nominal cost, and serve the purpose just fine, as people could just go in and change it when they want. A switch in the cabin would be overkill if it adds significant cost.