Boeing has been using shared physical buses for a while now in newer 737s as well as 777, and 787s
"Novel or Unusual Design Features
The Boeing Models 737-700, -700C, -800, -900ER, -7, -8, and -9 series airplanes will incorporate the following novel or unusual design features: Digital systems architecture composed of several connected networks. This network architecture and network configuration may be used for or interfaced with a diverse set of functions, including:
Flight safety related control, communication, and navigation systems (aircraft control domain);
Operator business and administrative support (operator information domain); and
Passenger information and entertainment systems (passenger entertainment domain), and the capability to allow access to or by external network sources.
The proposed architecture and network configuration of the Models 737-700, -700C, -800, -900ER, -7, -8, and -9 series airplanes may allow increased connectivity to and access from external network sources and operations and maintenance networks to the aircraft control domain and operator information domain. The airplane control domain and operator information domain perform functions required for the safe operation and maintenance of the airplane. Previously these domains had very limited connectivity with external network sources."