This is similar to shape change.
Templates kind of help, but don't quite do the job.
Sorry to say it again, but shape change is on the list. I'll work with Arsilon (and other creators) when I get to this so I can come up with a solution that will address the shape change power, lycanthropes, shape shifters, supers, and whatever else needs some way of having two swappable stat blocks for a single character.

