At the Detroit Auto Show, Watanabe announced that Toyota would offer a diesel engine in the Sequoia and Tundra in 2010. Toyota already offers a variety of diesels in the European market. However, according to Watanabe, the combination of diesel and hybrid doesn't yield enough of an incremental improvement in efficiency to justify the combined cost premium of both. At this point, the Toyota Hybrid Synergy Drive system is not suitable for use in the big trucks, which is why Toyota is following just the diesel path for now. Toyota USA VP Bob Carter told AutoblogGreen in Chicago that diesel hybrids are technically feasible and they are being developed (along with many other things as part of Toyota's $1million/hour in R&D spending), but Carter also said that the combination is not possible at a marketable cost.
One big difference between what was shown in Geneva and what Toyota currently has available is that the German hybrids were largely less expensive mild hybrids. These systems primarily provide start-stop capability and some electrical power boost. They also reduce parasitic losses by using regenerative braking energy to drive electrical accessories. One other thing should be kept in mind. Toyota Communications VP Irv Miller recently told us, "Flexibility is one of the beauties of Toyota."
[Source: Automotive News, sub. req'd via PickupTruck.com]