While it sounds reasonable, it gets complicated in the actual implementation. I've considered it many times, but the products aren't really related in such a way that makes that kind of linkage obvious.
For example, if there is a review - where is the link in PPPro? Why would a Photo Gallery also link to a Review? Same with Classifieds - how does a classified ad fit into the photo galleries and visa-versa.
I havent been able to come up with a design that makes sense - although the portal interfaces is a step in that direction.
Please do not PM me for support or sales questions. Thank you for your understanding.