this makes much more sense than tomatoes and is in line with my comment re vanilla (which could be much more lucrative).
The problem w vanilla is that either a specific bee species is required or each flower must be pollinated by hand. However, I saw an article recently about a ‘smart’ mechanical bee that had been engineered. Presumably, such a beast could replace hand pollination and avoid the environmental sensitivities of the live bees.
Vanilla vines take up a fraction of the space of cocoa plants and are prolific. I’m not sure if wholesale price/bean but retail is ridiculous. Successful greenhouse growing could probably cut price by at least 50%.