However, it is difficult for me to see how one would accomplish this with the Darwin Core Archives format, at least if one wishes to cut down on file size (and transmission time) using the "variable in a static mapping" shortcut.  The problem is what to use for the field names for the locally unique identifiers. 

I realise now that the example I gave won't work for this.   As I read it now you would like to use local integer identifiers in your database but expand them in the output file using a "template" that would conform to the template I used in my globals example.

In this case,  we don't want to refer to a different element we want the current element to substitute the local identifier it contains with the more inflated template.  In other words if your data file says that taxonID=100 has a parent taxon with an ID = 99 you want to conflate the integer with the more complete GUID following the template.