The current ( trunk ) implementation of Caliburn Micro introduces a new element in the phase of obtaining the view type name from the model name. The name of the View type is obtained from the name of the ViewModel type by applying a series of rules based on RegEx match and replace patterns. These rules has some defaults values, but others can be added externally by calling

NameTransformer.AddRule

There is an important default that is given by the following pattern:

NameTransformer.AddRule("Model$", string.Empty);

This is the rule that allow old model view naming convention works properly.

If you have some not up-to-date trunk version you can experience some problem, have a look at this discussion. The current doc of NameTrasformer is the source code of the ViewLocator and the ViewModelLocator from which you can derive what conventions are applied.