I've created a simple MEL syntax highlighting setup for BBEdit 8.0 on Mac OS X. It's available from the main page:

https://www.melscripting.com/

Look for the link labeled:

NEW! MEL Syntax Highlighting for BBEdit 8.0 on Mac OS X

Let me know if you find this useful. Note that it won't work with earlier versions of BBEdit because 8.0 is the first to support a text configuration file for syntax coloring.

-- Mark

P.S. It's free, and worth every penny.