I know this in some sense isn't free software, but I wonder what your thought would be on explicitly stating that an AGPL project for example was available for alternative licensing for pricing that could be worked out on a case by case basis (or even a fixed price). This makes it clear that there are damages in the event of the AGPL being violated without compensation, which would make a legal case far more viable. You could even refuse to do business with those that would violate the AGPL, but still claim damages if they violated so long as you weren't picking and choosing.