MHR, Leverage, and Smallville are all Cortex Plus games, but they are not the same games, as you can see. There is no "generic" Cortex Plus rules set. Instead, each game uses common terms, mechanical tricks, and concepts to work best with the license.
We are exploring the option of releasing a certain version of Cortex Plus (maybe even Heroic Roleplaying) for third party publishers, but we are nowhere near that point. We are great supporters of fan hacks and posting variations online etc etc, so the lack of an open game license does nothing to hinder you unless you're looking to publish professionally.
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