"String Enum" implementation - comments?
A few things don't add up for me regarding your usage.  You want compile time absolution, but dynamic values while stating the critical nature of its use.  

One option:
     You can just take care of this by having objects with inheritance structures and loading your "dynamic" values from an application configuration or db.  Just have 3 layers of inheritance 1) StringEnum 2) Enum Declaration (like System638) and 3) actual values.  Just wire up the inheritance.  Mostly likely though, interfaces would be more appropriate for restrictions at the 1 &amp; 2 layers.

Recommended (assuming the distributed smell of the use case):
     Build your functional class and bind it to a single DB table that ensures the integrity you are looking for.  Just cache the values in memory for performance needs.

Recommended (given the critical nature of its use)
     Find a different way to design the system so that you can fully embed what you need in code.  For example, a web service.  Even if you need a local presence you can utilize a web service to control the pieces you need.