KevinB, are you sure that it was a Fenton, though?
fentonfrk, thanks for your input. At first I thought it was just a cool glass oddity, but when I started asking Fenton collectors about it, they were all really excited & intrigued and one group even asked me to bring it to a national convention. When I say experimental piece...I understand that this piece is catalogued, etc. but it had to be invented at some point so I would think there'd be early experimental editions of it that may or may not have been destroyed.
I agree with cogar that the chances of it falling right in the center of the glass thickness in an X and not touching the top or bottom surfaces is really remote. Also I think the nails are longer than the width of the vase opening, so they would have had to have fallen in vertically and then fell into an X horizontally at the bottom where it's wide enough, and directly into the center of the molten glass so it doesn't touch either surface...I just don't think it happened that way. It looks too arranged in there.
Thank you Wendy! I did email Fenton a couple of months ago about it and haven't gotten a response, but I think calling them is an excellent idea. I will try to call them on Monday.