Same one that's been listed forever and a day, but now the seller has gotten it tested. Price is through the roof now, but make him an offer and maybe he'll accept?

no affil

http://cgi.ebay.com/NOS-B-W-Porthole-Round-Television-Picture-Tube-16AP4-/180588266976?pt=Vintage_Electronics_R2&hash=item2a0be645e0

$499 for the tube, + $75.29 for shipping? He can go screw.