"...and a Japanese automaker" Which would most likely be Mitsubishi as they are the only Japanese manufacturer with a production vehicle utilizing a dual clutch tranny (Lancer Evolution X).

Dual clutch is almost the only way I would consider an automatic and it is good enough that I would go without a typical manual tranny if my next car is available with the dual clutch tranny.

BW has certainly hit something of a home run with this technology. It cuts the cost of a fully automatic transmission, yet delivers better fuel economy. For engines with modest torque (<250Nm), further savings are possible by using dry rather than wet clutches.

Future drivetrain concepts may be able to deliver high fuel economy because of DCT technology:

Engines can satisfy a given power demand at various speeds, with the optimum usually somewhere fairly low down in the range (at high torque, e.g. via a small diameter turbo). If you take the engine's SFC diagram and draw lines of constant power in it, there will be a point or small speed range representing the optimum fuel economy for each power level. Connect these individual optima and you get a target curve, possibly with varying width.

A dual clutch transmission with a sufficient number of gears (e.g. 6, with long ratios) can always map the engine into an operating point on or at least near this target curve. Further accleration quickly forces a kickdown, but a DCT can handle those very smoothly - especially if the engine features minimized polar inertia. The result is a drivetrain with a susbtantially smaller, less powerful engine that is always operated as efficiently as possible. You simply no longer need the kind of massive torque reserve common in today's cars, because you can better anticipate kick-down events and minimize the discomfort they cause. Obviously, the solution is not appropriate for high-performance cars but it should make sense for urban runabouts and family haulers. Note that a DCT can jump gears if a hard kickdown is required, e.g. in an emergency maneuver: 6th -> 5th -> 2nd in the blink of any eye.

The target curve strategy can be employed with a manual as well, but it requires a lot of concentration and gear manipulation, reducing the attention the driver can pay to traffic. Conventional ATs with a high number of gears (e.g. 7, from M-B) are quite heavy, bulky and expensive.

Regardless of the transmission technology, a key requirement for driver comfort is to re-interpret the accelerator pedal as power demand. Currently, it represents torque demand, forcing uncomfortable foot positions when using high gears at moderate vehicle speeds.

Good to see the Quintuple word revived.

What's interesting is that dual-clutch transmission technology will be the thing that may obsolete the traditional manual transmission. The reason is simple: it offers the fuel efficiency of traditional manuals but offers the ability to switch to full automatic mode, which is very useful in urban driving.

@ Raymond -

Fifth Gear recently tested the new Audi TT with both
manual and DSG transmissions.

The DSG premium is still GBP 1000 (~4% of the manual's list price) but appears to be well worth it, even in a sports car. BW's announcement of a five-fold increase in production capacity suggests that the technology may become quite commonplace in European cars in the next few years, at substantially lower markups.