Here is an amusing one, I was watching a Bronica macro lens, serial # 10200612
http://www.ebay.co.uk/itm/BRONICA-ET...-/151110440429

And its been bought and immediately relisted at over double the price!
http://www.ebay.co.uk/itm/BRONICA-ET...-/310751865942

Buyer beware, often the BIN's are complete nonsense. I've been keeping a list of Bronica lenses too, and this BIN is wildly over-optimistic, relative to the normal price.