Two years ago I released a Maya skin weight export/import tool, “Skinner”. I’d released the code for free, but obfuscated. And sold the source to interested parties.
It’s been used in AAA production at multiple studios since that time, and (unless I’m simply unaware) it’s the best skin weight tool on the market, for a variety of reasons (see it’s docs for details).
Unfortunately, the obfuscation tech has become a pain to work with, which has been preventing people from using it, so I’d decided to open source the whole thing in its most recent package:
But I’ll still happily take donations for its usage! 
If you’d like to ‘support the cause’, please see here:
Enjoy everyone, and cheers.