I don't know where you live, but around the NY area, Navigators and Yukon Denalis are popular with livery companies. Every time I call for a car to the airport, one of them shows up, especially now that the Town Car is gone.

With that said, one does have to keep in mind that, if the 5.0l gets an update, the 3.7l could foreseeably get one as well. With direct injection it could see over 330hp and 290ft-lbs of tq like Hyundai gets from their direct injected 3.8l. That would be perfectly adequate for a base engine in the navi/expy, especially if both see a bit of a weight reduction.