There is nothing I know of out of the box that accomplishes this.
You should be able to write a custom component to do this. You will need the following:
1. Run a search to find all CDFs that have a particular xRegionDefinition tagged on them.
2. An XML parsing library.
3. A mapping between the new values in the Region Definition and what should be replaced in the CDF.
That sounds like a plan. I have experience using several filter hooks, namely 'validateStandard' and 'validateCheckinData' however I understand that these will only be executed on check-in. Is there a filter that you would recommend to make these changes on all CDF's within my content server?