The mastermind atom has a very cool new feature upcoming in the next version of oclhashcat-plus. He calls it "multi-rules".
With them you will be able to combine an unlimited (as much ram you have) rules files.
http://hashcat.net/forum/thread-703-post-3472.html
Hey Guys,
I wanted to give you a sneakpeak to the latest oclHashcat-plus feature coming with version 0.07.
This feature goes back to an suggestion from Hash-IT, see here: http://hashcat.net/forum/thread-645.html
Again, thanks for this!
Since no other cracker have this feature, I had to find a name for it.
I will call it "multirules".
Instead of just giving one -r parameter and a file, you can now add as many -r's as you want.
But they are not just appended (or executed in serial).
They are combined. Each rule of each rule-file is combined with each rule of each rule-file (see original post above to see the details).