...This unidentified bidder at Sotheby's auction in New York on Wednesday bid $95.2 million for a Picasso and $2.5 million for a Chagall. Yesterday that man's face was being sent by e-mail around the world, as art dealers and collectors frenziedly speculated on his identity. He ended up spending $102.7 million, for a 1941 Picasso portrait, "Dora Maar With Cat." ...an 1883 Monet seascape for $5 million...a Chagall, a 1978 biblical scene, for which the man paid $2.5 million But who was he? Sotheby's has refused to say. It is unclear whether he was acting for a client or buying...