Well the other night I was sitting at the house and really had nothing to write about so I decided I was going to write about how to design a landing page that will really sell your product you are promoting. I know for fact that my method works due to selling 3 products in the first week of opening a landing page I made with no knowledge of marketing one. The whole write up is at my blog. http://www.unitedhustle.com/design-and-development/landing-page-designs-that-sell
well, you mentioned giving a space to likes of ebay and amazon. I think this would distract the visitor...main goal of landing page(lead/sale) gets sidelined. May be ,it works in some cases as you get extra arms to pull profits from bigger brands.