td-01 chinese tonearm?

Nope, thats not it. I have a Hadcock and its not what I am thinking of. Maybe a Helius or a Basis Vector. 3 balls creating a triangle, with a 4th ball in the center and raised above the other 3. Maybe I just thought of it?

I think it was the Helius Orion first & the Cyalene later using the 3+1 balls.
I recall some similarities with the old monophonic "Gray" arm that uses grease (instead of oil in the TD-01)
Another thing that differentiates the WT is the great mass at the pivot point.

I think the arm Manitunc referred to was the Wilson Benesch Act 0.5:

http://www.stereophile.com/content/wilson-benesch-full-circle-turntable-act-05-tonearm-ply-mc-cartridge-page-2

Mystery solved. The TD-01 arm does, indeed, work like how I described, ie, the string hangs the arm and the ceramic ball does not touch the bottom of the oil pool and only for stabilizing. Seller responded to question.

Hi, the arm being hung by the string and the ceramic ball is not touching the bottom of the oil pool, thank you! Best regards.

Whether that's a good idea or not is up to the potential bidders to contemplate, I merely described what I observed.

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I would think that there must be something holding the arm in place in the cup other than the ball floating in the oil pool. I would think it was either sitting in the bottom, held by the weight of the arm or the string would go right through, which obviously it does not. the description above makes it sound like the arm is on a pendulum, with the ball just touching the surface of the oil to slow the pendulum action down.

I would hope the ball is actually sitting in the cup and held in place by the weight of the tonearm and the string just provides lateral support.