Sources indicated that up to US$161.4M in ad space ???will go under the hammer during the auction period, with the unsold inventory then being put on sale to advertisers who are not Olympic partners.??? For the first two weeks ???only the 18 worldwide, tier one sponsors are being allowed to bid -- brands such as Coca-Cola, BP, Samsung, Lloyds TSB, BMW and Visa.??? The ???first lots on the block ar