Where Have You Been Hiding, Jonathan Cheban?Sometimes you have to make an effort to reinstate communications with (or in our case, about) old friends who you haven't spoken to in a while. We used to write regularly about the travails of Jonathan Cheban: party boy flack, designer, and former Access Hollywood correspondent and Lizzie Grubman partner. But we've said barely a word about him since February, when he supposedly registered at Barney's for his own birthday party. Jonathan is simply too crucial a character in the celebutard publicity machine to go unnoticed. We hear he still leads a very eclectic social life. What do you hear? Anyone with important Cheban information, please email us.