RAV4 is a unibody AWD crossover - no Tcase needed or wanted. The Suzuki Tracker is descended from the Samurai - a genuine, body-on-frame SUV.
Don't know if the new XL7 and Vitara have Tcases or not. They look like CUVs with 4 wheel independent suspension and sit pretty low which makes me think they are unibody rather than body-on-frame.
Remember that most unibody crossovers have transverse-mounted engines i.e. the crankshaft of the engine is parallell to the axles, wheras most conventional body-on-frame trucks and SUVs have the engines in a longitudinal configuration i.e. the cranshaft of the engine is parallell to the driveshaft (the notable exception to this is Subaru, which still puts their boxer engines in a longitudinal configuration.) With the engine in a transverse mounting, the engine sits on top of the transmission and front drive axle, or transaxle. In AWD versions, a driveshaft sends power to the rear axle via a viscous coupling on the transaxle. Most "AWD" cars are actually FWD until the front wheels start slipping, at which point the viscous coupling engages and sends power to the rear axle.
On the other hand, in a conventional body-on-frame SUV or pickup, with the engine in a longitudinal configuration, the engine sits in front, the transmission immediately behind, and power goes to the rear axle via a straight driveshaft from the transmission. In that configuration, it is relatively easy to stick a transfer case in behind the transmission to send power to the front axle (or not.) But it would be very difficult to put a transfer case on a transverse mounted engine.
