Has anyone he heard of Amazons practice of buying or taking over a sellers listing and offering them a percentage?
I think that your thinking of Vendor Central.
Take a look at the below.
An acquaintance of mine with a fairly large online business told me she had been approached by Amazon to take over her listings, an advantage I suppose as they told her the listings would be highly prominent.
However she delinclined because of the lower earnings potential and of course no guarantees from Amazon.
I must admit, I would be extremely wary of passing over control directly to Amazon for a product.
They just want too much usually.