You should investigate if your cart system can do product options such as color and shape in order to reduce down the number of installed products. I'm sort of repeating what some have said above, but I have had experience with this. It is of no use at all to write garbage descriptions for each product that is basically the same (been there done that). Try to condense them as much as you can. Keep usability in mind. It makes more sense to land on a page about square widgets and see a drop down to pick the color than have 20 different colors of square widgets installed as products. If you want your site to look "big" by doing this then it won't help you in the eyes of google at all.