Instead of having toll transponders in your car, you could turn on a phone app that tracks where you are, knows your credit card and vehicle details, and auto-submits them to toll collector websites when you go past toll points. The various toll operators would match your self-reported location with their video logs and charge you appropriately for the day. You could even arrange it so that multiple people per trip spread the toll out between them, by all using the app at once. That way you could automatically share the cost for, say, a car pool. Of course you'd need to get the toll operators on board with this, but at least then you wouldn't need a different transponder for every operator.
Mokalus of Borg
PS - This is my 2500th post!
PPS - There should be a cake or something.