I think the only recorded sale is a 4k Vamp 5 from NYC. I don't have access to their private sales, of course, but I consider that an outlier and if you look at the GPA data (and yes it has weaknesses) it is an outlier. But I am guessing there are previous private sales that justify this price. How many people are really willing to drop thousands for one of these non-key mags? The amazing sets we have seen here were purchased for circa 300/book cost (thereabouts). I am being offered another Vamp 5 for 6k based on that NYC price point recorded in GPA and the apparent belief that the Frazetta signature increases in value every month. Us latecomers to the party are certainly screwed unless we are happy to get just one example and call it a day. That's not really my style, but I also can't justify being into these for 5k a book when looking at a nice run of 13 books (I get the number 13 from the census numbers for which more than a single copy exists, tracking singletons down would be crazy and I can only imagine the price for that example).
I do think the 1500 sig price may be a decent ballpark estimate though. When you look at the numbers and consider that many of these Warren mags are not that valuable 1500-2000 per book seems about right, with the exception of the Vamp 1 sales and the recent Vamp 5. Then you get amazing things like a Vamp 11 7.5, only SS in the census, that sells for 1200 in 2015!! Stuff like this is why I balk at prices of 5-6k per book. On the other hand, if someone came to me with a set of 10 of these at 2k per book I would write them a check for the lot without much thought.
I honestly don't see much upside at these prices considering you really start butting up against original art prices. For example, I could buy the Vamp 1 reissue at a 9.8 for 10k. Instead I bought Frazetta's original Lord of the Rings sketchbook for just a little more (10 original drawings, all initialed, several prelims for plates that were never released). So I guess the opportunity cost for these is too high when you look at what can also be bought for similar money. At least that is how I see it. Maybe there is less crossover of collecting graded books and OA than I realize. And as I write this I think maybe I don't have the mindset for collecting CGC books. Regardless, I would be a wealthier man if I had never discovered this thread
As always, just my 2 cents, am no expert nor claim to have any real knowledge of the industry. Thanks to all who responded to my PMs and thanks to the posters who have shared their images here.