Ah, the fabled JOPAD diet. I think the problem might be that typical peanut butter has at least 2x fat vs protein. So 3000 cals of peanut butter would be like 120g protein, which is not enough. And it would be over 300g of fat.
Santana might have more accurate numbers, and might be able to figure a way to fit this into an overall solid diet. For me, it would be moot, as I could not eat that much peanut butter more than once. And I like peanut butter. If this is possible to do, however, you are the right guy to do it.