At the risk of drawing too much attention to this auction... if folks here are trying to win it, perhaps they could coordinate to ensure the board is documented?
http://www.ebay.com/itm/151675918064NeXT-branded; 3 BNC connectors.
Theory: a video-out board that outputs mono over RGB for connection to a projector or larger monitor? NeXT would have had to have one of these for product introductions and demos...
If someone gets this, you'll probably need to buy the motherboard he is selling too. It has the extra chip that might be needed for this board to work. Seems like that was part of the discussion last time as well.