There seems to be an opportunity that I can't find any holes in.
Yet I'm sure there must be or someone would have done it by now.

Would any sponsors support the idea of mentioning a copywriter in a mailshot to their affiliates, or with a content update? And if not, why not?

Surely it helps the sponsor if their affiliates use original copy from the short text they supply, as it secures the affiliate more traffic and your site more revenue.
And surely it helps the affiliates if they know who to go to for original copy?
And it would certainly help a writer like me to build a good client base.

So, any sponsors have any thoughts on why this hasn't been done (or maybe it has?), and what would stop you from teaming up with a writer in this way?