I am a Distinguished Research Engineer with EarthLink Inc. R&D (see http://www.research.earthlink.net ). I live in the San Francisco Bay Area and have been using Tcl/Tk for quite a long time. One of my projects is a video-chat, video-presence application that consists of about 30,000 lines of Tcl/Tk code, along with some C and C++: http://www.research.earthling.net/confmgr/ . Notably, due it large part to Tcl/Tk, the application runs on MS Windows, many flavors of UNIX, and Mac OS X.
Find out more about me at my personal page: http://www.bdt.com/david and my blog at http://mrblog.org .