These are on ebay right now, I'm pretty sure I've seen them before. At least twi different sellers. They emphasize it as "high quality" and prices ranging from $225 +$8 shipping to $287 + $19 shipping (depending on seller).
intent://www.ebay.com/itm/135493923577?
They're simply called "AM BROADCASTER TRANSMITTER". No mention of certification, but that's not why I'm bringing it up. I dont personally know of anyone using tube transmitter for their station, but you know I have always heard tube type transmitters produce better sound.
Here's part of the description of one of them:
"..I settled on the original design back in the 90's with considerable refinements to provide much cleaner and more effective output power with wideband audio response (not limited to 10Khz) for a crisp alive sound but still have the warmth of sound in tube based operation. The Broadcaster is extremely frequency stable. Tuning range is 630Khz to 1630Khz...."
146466781707