As for your patrons, with great wealth may come great responsibilities, but buying an original by, say, Brice Marden is not one of them. In a sense, great work is immune to imitation anyway. It's one thing to say you're going to paint a picture in the manner of Pollock, quite another to do it well. Your knockoff will inevitably lack essential Pollock qualities. To modern eyes, what is most striking about those convincing counterfeit Vermeers of the 19th century is how little they now resemble Vermeer, and how much they look like 19th-century painting.
People buy things for many different reasons.
The customer for one is not the customer for the other. Indeed, the copy can enhance the value of the original by declaring it a work worthy of imitation. These issues are much debated in the art world as both ethical and aesthetic questions, and there are painters who would resent what you are doing. However, artists as various as seventh-century Chinese calligraphers, Marcel Duchamp and Sherrie Levine have challenged the idea of the proprietary original. If you get busted for your artistic endeavors, and those folks are on the jury, you'll walk.