I so agree with the suggestion of M Keyes.  Giving credit to the merchant/vendors for products used should be the primary prerequisite for gaining a place on any of the art charts.  Since Renderosity has in place the apparatus to credit our vendors surely this can be accomplished. 
To be recognized as a cut above all others,  there should be rules. If one wishes not to include the information then their renders should remain in their individual galleries still receiving comments, favorites and recognition from other art enthusiasts .  I think showing recognition to our vendors would benefit the entire Renderosity community in terms of respect, growth and financial reward.  (I have in mind Motion Picture credits, Musical Album credits for examples)

Even if the products are purchased, my point is, just who receives recognition  in the art charts.  The art is not a product of the submitting artist alone.  My thoughts above pretain ONLY for the placement of artwork in the art charts.  JUST WHO HELPED THE ARTIST TO GET THERE!