I found a few threads on this but they were a few years old.  I wonder
if anyone had done this recently and if there were any updates or new
information on it.

We're doing not only a CM but an enterprise application.  Documentum
must speak not only to the web but also to a few exposed web services
and a legacy system we'll wrap in a web service.  We had thought of
customizing it and using Struts or Spring into the Documentum
foundation classes.  Now we are seriously thinking about leveraging
their WDK and trying to extend to work with these services.