Please forgive my ignorance on this subject matter and the legality, effectiveness, etc. of what I may say.
Wouldn't it be a simple matter of rewording the license in such a way that it would limit the use of the solutions only for development purposes and not for resale of the standalone basic package? Or even for a price lower than the original purchase price? Something along those lines could probably be looked into that would deter the improper use of the solutions by unscrupulous users.
Again, I'm not knowledgeable at all on this legal matter, but thought thinking along this line would be a positive direction on the problem at hand.