homepage at http://freewrap.sourceforge.net/
There are various forms of this application - from wrapping pure-tcl scripts to wrapping tk and I believe even tk + certain extensions. The pure Tcl version--freewrapTCLSH--generates an executable that's typically just over a quarter of a megabyte.
Alex [Vizantinos?] provides a recipe [L1 ] for reverse engineering a Freewrap-ped application. Dennis follows that up with a simple counter-recipe for use of a private encryption key.
Latest version (5.6) gives up source code encryption [L2 ].
See also tbcload.