As of right now, I've turned things inside out the other way around.

My VBA function now dynamically writes out the requisite perl script as one massive text file (that loads the lexicon once, then runs all of the individual queries in the same script so that the lexicon object persists obviously until the end of the script), and then calls that text file back into the shell inside VBA.

So, right now I'm actually driving Perl from Excel. Very strange. It seems to me like a really ugly fix, but it works fairly well... except when it comes to recalculating anything, and the formula has to regenerate the text file and reload the lexicon (since it, as always, closed after the last dynamically-generated script finished).