It is "possible" - the manus should have introduced them long ago, IMHO. If they are real they are engineering samples most likely. My bet would be "BS" unless he is somehow connected to the industry. The problem with spinning the drives faster is that you have to reduce density - meaning smaller (storage) or larger (physical size) HDDs. That is why you don't find 100+GB 15K SCSI drives out there. See if you can get manu, capacity, platter #s, physical size, etc. and screen shots of device manager, sisoft, HD tach, etc. Get him to put his proof where his mouth is. He can black out serial #'s if he is worried about legal issues, but If he won't comply with the above request it is probably just BS.
I thought a thought, but the thought I thought wasn't the thought I thought I had thought.