Currently, at iDirect [L1 ], we are extending (also means rewriting) our network building desktop app with Tk.
This means lots of MFC/Tk interaction (embedding Tk windows into MFC Views), SWIG, iTcl, BWidgets and other stuff. We are migrating away from MFC/Stingray and find that with a few custom written widgets (network diagramming, date chooser combobox, ip entry widget, etc) we can do just about everything MFC/Stingray can do (and it even 'looks' better ;-). Visually (because of BWidgets and some custom tweaking on our part), you can't tell the Tk stuff from the MFC stuff.
-- Todd Coram