If you're one of the many who love the coddling that goes with any visit to an INFINITI dealership, but you're in the market for a sport-utility, take heart. With the arrival of the new INFINITI QX4 you can have both. And you can probably thank your INFINITI dealer for this addition to the lineup. In recent years the purveyors of Nissan's luxury cars have been wistfully watching the steady growth of the luxury sport-utility market, particularly the sales that were lost to the new entries from Acura and Lexus. In particular, the incremental uptick in sales that went to Honda's Acura division, when it added a rebadged version of the Isuzu Trooper to its lineup, provoked a howl from the INFINITI dealer body. The dealer outcry, obviously, did not go unheeded. During the development of the popular Pathfinder, Nissan also worked out a parallel plan for an upscale version to wear an INFINITI badge. And here it is.