@Expand Online: You are absolutely right when you say more links don't pass the double amount of link juice, but I hear stories that a second link does pass a bit of link juice and takes away some of the advantage. Just wondering if it helps to make sure you just have one link for each product without thing away the usability for the visitor.
@João Vargas: It's not about cheating a search engine, it's just trying to make sure we are not wasting any unnecessary search engine resources. I'm not to sure what you mean with the second paragraph in your message though.