As a merchant, I would say it would be hard to automate this, but this is just my first impression.
However, the fact that it would be difficult to do would limit your competition.
Remember that affiliates (usually called sales reps) existed long before the internet did. So people made - and still make - money pitching other people's stuff in the offline world.
So I think you have to look at your competencies and determine why they SHOULD use your services instead of selling on ebay, or amazon, or etsy, or some of the other sites that are geared toward "internet challenged" businesses.
Anyway, hope there is an easy solution for you and I hope that someone with more knowhow about these matters chimes in.