A couple of updates on the two huge Manhattan deals reported yesterday, at 3 East 94th Street in Carnegie Hill and the penthouse at Soho's 459 West Broadway. The mystery buyer of the $18.5 million limestone UES townhouse is American Express CEO Kenneth Chenault (right), Page Six reports. And the Wall Street Journal spoke to billionaire Leonard Stern about his new "ultimate Soho penthouse," which he bought furnished for $14.25 million. He's considering relocating there permanently from his Fifth Avenue mansion, but only time (and market conditions) will tell. [Page Six; WSJ]