You may not have a home in Pacific Heights and a summer place at Emerald Bay and a chauffeur to tend to your two Mercedes and Junior's Alfa Spider, but at the Fifth Floor you can pretend you do -- and the maitre d', chef, bartender, and busboys will encourage the fantasy. When you emerge from the Palomar Hotel's elevator into the Japanese-accented foyer, make your requisite stop at the clubby, handsome bar for a Bombay Sapphire martini, then settle in for a long and pleasurable evening amidst the silk, ebony, and burnished silver of the dining room --the mood is prosperous, the surroundings are lush, and the menu drips with foie gras, quail, caviar, and lobster. The tariff is predictably steep -- but that's what expense accounts are for, right, old man?