When I worked for Zattoo (leading TV streaming provider in Europe; B2C+B2B business), we developed a dynamic ad insertion technology that can do exactly that but without any hardware:
https://www.broadbandtvnews.com/2017/03/20/zattoo-offers-dyn...
It replaces ads in a unicast stream with targeting down to an account level - at least from a technical perspective. All server side. No box required.
Feel free to reach out if you want some feedback, advice or industry insights. Love your idea!