IT MAY be called The Lost City but it certainly isn't a lost cause financially. Hong Kong's newest and most baffling entertainment complex opened in Tsim Sha Tsui last week in expensive fashion. The 'theme' multi-plex built inside a former hostess nightclub was officially opened by a flag-waving Leon Lai-ming. The singer reportedly got $500,000 for doing the waving (Leeeee-on's the going rate for a full-blown ribbon-cutting starring Leeeee-on is closer to $1 million) and the crowds duly showed up. So too did the radio people from Metro radio who have landed an interesting contract whereby they handle publicity for the complex and in return get to set up a booth right at the entrance to the club for the occasional live broadcast. They don't call the place The Lost City for nothing: it's not hard to get lost in the 80,000 square foot basement complex in Chinachem Plaza, which is divided into 12 'districts' with names like Somewhere In Town, Zebra Disco and the Champs Elysee VIP Room. Interestingly enough, the place's target patrons are said to be hostesses from the other nightclubs who might choose to take their customers for a nightcap.