I was thinking of something like this for the rear of the helmet:
https://www.ljeproducts.com/shop-pro...d-helmet-light
Look, it's made in Pembroke, NH!
I'd probably put it on the rear of my passenger's helmet, or I'd need two, and only turn on the rear most unit.
This may be a diversion from the RideLite discussion.
Here's a link to the Ride Lite for those that want to know more about it (They are based in Vermont):
http://www.communicationsafetysystem.com/home.php