Interesting JV Concept? Are People Doing This?

First of all, I just want to say that the reason I didn't post this in the JV section is because it's not an offer. All I'm doing right now is thinking about a method of doing business, and I wanted to see if this is already being done by some. I also want to know if this kind of thing might actually work well or if the whole idea might be flawed from the beginning.

Imagine that there are marketers with a great list of subscribers and a few great products they are marketing to those subscribers. What these marketers do not possess are the skills needed to write a good sales-pulling email. Someone else, a good copywriter, steps in and offers to write the emails for either that marketer's own products, or the ones they're affiliated with. In exchange, the copywriter wants only a cut of the sales after an email campaign. It's a win win situation, because the list owner owes no money upfront, yet the copywriter knows they can make bank once the money is earned from sales.

I'm absolutely positive that there in fact are list owners who do not write good sales letters to their customers. The only thing that I can think of that could stop this method of business from becoming a reality is that there may not be a way for the copywriter to know if the list owner was being honest about how much money was made due to the email sent to his list.

Maybe this kind of thing is already being done and I just don't know about it. Let me know what you think. Maybe some of you have already tried this?