rehydrate

Are there design patterns for writing SharePoint workflows that will be upgradable?

Howdy, I have asked a question on another thread about upgrading long running workflows and have not received an answer that I wanted to hear. (http://stackoverflow.com/questions/357032/how-to-upgrade-a-long-running-sharepoint-workflow-already-in-production) The answer, which matches up with the other research I have done on this topic...

Is there any way to know that an EF4 entity is rehydrating?

And, if not, what pattern should I use when adding this into the T4 templates? ...