Please allow to hide classes by stereotype using the "hide" keyword.
Example:
@startuml hide <<tag>> class bob <<tag>>{ } class joe{ } @enduml
This would hide the class bob.
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With last beta https://dl.dropboxusercontent.com/u/13064071/plantuml.jar
You can now have:
The result might not be exactly what you are expecting : the class is really "hidden" (there are some space when it should normally be printed).
Tell us what you think about it.