The trick is to just accept that the UI model, the business logic model and the denormalized db model all have different goals and often times should be decoupled and adapted.
Which is why it seems almost every project with a complicated UI turns into a bloated pile of semi-duplicated boiler plate 'model' classes with little business logic. Clearly, MVC as the industry understands it, has a problem.
Which is why the original Smalltalk people -- who invented MVC -- mostly switched to Self's Morphic framework in their later projects (Squeak, etc.)
