Multiple Near Near Identical Pages - How will it affect rankings?

I have an ecomerce site that is totally database driven. Not the best thing for search engines.

I am going to write a script that can generate a static version of the site so that it will be faster (I don't update the site enough to warrant hitting the DB each time) and more search engine friendly.

My potential problem is that I'm going to have multiple near identical pages...

i.e. The way the site is designed now, the individual product pages(that feature a single product) also have a menu on each page with only a partial listing of items. So while looking at item A you are also seeing item A,B,C,D,E in the menu. If you click the buton to advance the menu you will be seeing item F,G,H,I,J in the menu BUT you will still be looking at item A as the individual featured item. (to get an idea you can go to tiffany.com
... click what region you are in and it will take you to my example.)

So, the potential search engine problem is I will have multiple pages for each item... the only difference between the two is that the images in the menu will be changed. Right now there might only be two near-identical pages per item but that could increase if the inventory grows.

Would this dilute my search engine rankings?

Thanks for sticking with the long explanation. If you need more info or a clarification I would be happy to provide it!