Limited Editions of LV

I'm not sure of any website, but I've called LV (1.866..) and said that I need a price on a past bag and they were able to give it to me.
 
What I also do is just go to ebay and do a search on the item, usually I get a pretty good idea of the current worth of the item (assuming the item is authentic on ebay.. you just never know nowdays.)