I could add that to the database in short order, but there are a few problems:
Echoing what David said, it's difficult to keep up with and very subjective. It would be better than the pricing guides however. They have been, shall we say, less than honest in their intent. On the other hand, it's often said that the current price = the last price the item sold for on Ebay. That's trackable, but difficult manually.
Right now, I maintain the database solo and haven't had time to keep up, let alone add pricing data. I like the idea, but in the vast majority of cases I'd have to go back to Ebay, find the final price, and then modify the glass. Even if I had helpers, the information would have to be vetted.... Hmm, let me think if there's a way to do this. I'll keep it in mind for the next database upgrade. There are a lot of ideas rolling around in my mind for Q1 2016.... any data would be better than no data, right?
Thanks for the suggestion....