ILOG has come up with rules for COBOL. I came to know about this a while back, but ran into this post by Daniet Selman (ILOG JRules Rule Studio Lead).
The effort for rules extraction from Legacy systems have been in place for quite sometime now. Rules For COBOL approaches in a different way.
The advantage with this approach is that enterprises can divide-and-conquer their legacy modernization, incrementally externalizing their business rules from COBOL applications and moving them into the BRMS. They can continue to execute the rules as COBOL minimizing the disruption to their system infrastructure.
Interesting. Now gotta learn mainframe to check this out.