I would also be interested in any complete reply to this question. At one time I recall there being some intent to include perl and python in future releases of eggdrop.
My thoughts are that the problem is not so much the embedding of the core scripting languages themselves but the inclusion of equivalents for the great many Eggdrop Tcl binds and commands that have been added, without which even Tcl would be pretty useless.
There are Tcl scripts that execute other language files, for example the timed execution of the perl script pisg in order to generate channel statistics. Likewise, I don't doubt python scripts can be executed in the same way. However, I doubt that this is an answer to your question.
With the current 1.6-tree, No. Tcl is way too integrated into eggdrop's engine to easily be replaced/extended with other languages. You could of course use tcl's ability to interact with external applications to make use of an external parser. This would though be run in a separate environment, and the only thing these two applications would share are pipes.
There is/was some ideas about pluggable script engines in 1.7/1.9, as well as removing the dependency on tcl, although I currently have no idea regarding it's progress, or the overall progress of 1.7/1.9...