they are the same things with a size, colour or quality change so you end up with the same old description re-written several times over to avoid duplicate content...
I have this situation too.
I always place all color and size variations on the same page. If I have six colors I will show a photo of each color and place an "add to cart" button below it.
This accomplishes many things. It makes comparison shopping easy for the customer, It reduces the amount of work that my webmaster must do. It reduces the number of pages on the website (and I believe that makes a more competitive site).
Although that does not give me separate pages for "red wooden widgets" and "blue wooden widgets", I will still get a lot of long tail traffic because I have those colors on the page, often in the title tag and the extra long description helps my page pull long tail traffic.