In the 90's I had a small consulting company specialized in factory automation. The FSM (and other) technology was done by me and my team and was funded by a $750K project we had won. It was later used in many other automation contracts, and in fact is still running some fabs 24x7 yet today.
The rewrite I have done myself, taking all the concepts and lessons learned and using more modern tools, such as a modern Parser Generator. The original was done with Yacc/Lex.
Re: Open Sourcing it... I have never really understood the benefit to giving away software, unless it's something that warrants a group effort in development. And for those, my experience so far has been if it's needed, someone will usually fund the development. But, I am still open to the idea of open sourcing it.