Bob,
I have a few questions on a couple dialogs...
I notice that "verbs.h" is included in the headers. I see this is for the 'verb_num' argument that's been added to the Dialog constructor. I looked in Dialog::Dialog() but it doesn't appear to get used in that function for anything. It would be nice if we didn't include verbs.h in the dialog headers, because verbs.h changes often and would force the dialogs to be recompiled excessively. What is the verb_num argument for?
Regarding naming, Jizzbug and I felt that the new dialogs should not have 'dialog' in their title, as it's redundant since they're in the Inkscape::UI::Dialog namespace already. Would it be possible to rename TraceDialog to Trace, and ScriptDialog to Script?
In TraceDialog, I notice you have a TraceDialogImpl class; it turns out that due to DialogManager, the dialogs are encapsulated well enough that we really don't need to use the Impl trick.
Anyway, nice to see all the new dialogs in gtkmm. :-)
Bryce