Woo, saw the first, mythical widget call today! I just instantiated a GtkButton with only an XML description of the function. I kludged a bit of it, but I can straighten that out when I get to work on the rest of the generalizations that I need to do. I probably wouldn't have been able to do it without help from Jeff Epler, many kudos to him.
Ugh, forgot to commit my changes to my CVS server. Guess I'll be working on something else until the firewall goes down at noon.