To be clear, that example concentrates exclusively on modularity. It doesn't demonstrate integration with other Prism v.4 features. It's MVVM is primitive ... one of the first MVVM samples around and it predates Prism v.1's separated UI patterns.
Clearly in need of a refresh. I've been hoping the DevForce community would take on the Prism v.4 Survey RI.
We want to do it. It is not a priority at present. We'd happily support any volunteer effort!