I like the idea of giving them a taste of their own medicine. That would be great. However, I don't think those drivers that are doing the excessive honking would choose to by such a vehicle.

How about car horns that, instead of emitting sound, emit a signal that triggers a quiet honk inside nearby vehicles? This would limit the ability of drivers to communicate with pedestrians, but at the same time it would reduce the noise pollution for local residents.

Back in 2003 someone posted an idea about installing two car horns in all cars; a "friendly" horn and a "hostile" horn. This was my response:

After living in New York City for thirty years, it's been my experience that car horns are rarely used for their intended purpose, to alert other vehicles of potential danger. Instead, their primary use is for the venting of frustration, anger and hostility by the driver, and unnecessarily contribute to the high noise level. It occured to me that to fully function in this capacity, horns ought to be installed on the inside of the car, not the outside. This would contribute to the gratification of the honker while creating less disturbance to those in close proximity.

In other words, I totally agree with you.