I would be interested to see whats going on with your "long tail game". Long tell keyword for me = money, So... I wouldn't jeopardize ranking for "Red Polo t-shirts" just to rank better for Polo t-shirts. I would suggest maybe boosting up the unique content on your Product pages to make them rank better for specific long tails. I like the fact that all of my product pages are indexed individually just for the simple fact that I have a customer base that google's Part numbers. Those product pages show up every-time and almost every-time it rings the cash register. This just might be something to think about... but if all of your product pages are duplicates then they are not helping with the long tail so I would say canonicalze them and redirect them to get rid of the dups and see if it helps with those head terms.
Hope this helps
Chad