When you said "sell it", it excited the reptile part of my brain.
That said, I read Why is EDI still used, and how to deal with it? Yikes.
I looked at About Bots edi translator software. Quote: Programming language: Python.
Conceivably, one could use Inline::Python to interface Perl to the Bots open source edi translator.
(Fortunately, it seems that the authors of both pieces of software are active.)
GotToBTru, you mentioned a grammar approach. The Marpa::R2 folks are always looking for niches where Marpa can demonstrate its prowess.