Redbook

As far as collecting sales prices to publish values in the RedBook, the majority of data comes from aggregated dealer sales. ebay has to be ignored for the most part because it is a flawed marketplace with the vast majority of coins sold by amateurs and not professional dealers. That may sound like an elitist statement but it really is not. Many variables affect the sales price on Ebay- the seller's reputation, quality of the photos, auction list indexing, shipping costs and location restrictions, etc. You could give the same coin to two different ebay sellers and the final prices could have a difference of 25-50% when all of the variables are factored in. Give that same coin to two professional coin dealers and the sales prices will be fairly close in many cases.

Then you also have an issue with the flood of problem coins on ebay, how would you take them into account when publishing pricing data? Yes, dealers also sell problem coins too but the problem coins that dealers do not touch with a ten foot pole typically end up in places like ebay where the coin might be doctored and the images photoshopped all in the name of getting higher bids.

The expectation that Whitman Publishing, or anyone else for that matter, publish an accurate pricing guide for coins is doomed to failure. Many posters here have explained the complexities and variables involved but that informaton seems to be rejected.

I'd recommmend the OP take his idea and bring it to market. The only issue I see is getting the collecting community to adhear to his price guide. As soon as the mandatory price guide for coins hits the market, I like the sequel in the series to address pricing on automobiles.