Mark N. Gibson writes:

The heart of it is that I'd like to have the Zope evaluate an arbitrary string as if it were a DTMLMethod You may want to look at the DocumentTemplate packages.

This packages is used to implement Zope's DTML objects (these objects add persistence which you do not need). One of the source files, I think it was "DocumentTemplate.DT_String" contains a good source documentation which tells you how to use DocumentTemplate in your Python code. Dieter