It would be very useful to have entity templates. This templates should include both metadata and business logic in order to be the foundation for the design of new entities. In this way we could easily add common functionality (loggin, audit, business actions, etc) to new entities without having to cut-paste and rewrite stuff. It would be great if template's updates were inherited to entities designed based on them.
Andy Kung commented
You might be interested in LightSwitch Starter Kits http://www.microsoft.com/visualstudio/en-us/lightswitch/starter-kits. It aims to give you a good starting point in building common business apps.
Petr Tichý commented
Huh, what about class inheritance? Would make that the same but standard way? I would definitely vote for support of class inheritance (but I have no more votes :-() ...