A little birdie told me a few things about this vehicle, and we can figure out a few more things for ourselves.
1.4 3-cyl TDI engine 85 kW (115 hp) - that's not a bad starting point. Presumably this will be commonrail and with all the new Tier 2 bin 5 emissions equipment - pretty much three-quarters of the new 2.0 commonrail TDI but with the old 79.5mm cylinder bore.
Motor has 15 kW (20 hp). The combined torque curve of the motor and engine is very good.
The mechanical layout is not unlike VW's earlier electric-hybrid prototypes - they've been doing this since the 1980's. The deal is that there is a single motor/generator between the engine and the gearbox (which is VW's now-conventional DSG - which I don't mind - but it could conceivably even be a row-it-yourself manual gearbox). Honda's system was like this, too, but the diff is that VW put the electric motor on the gearbox side of the clutch (the clutch is between the engine and the motor/generator) - this allows full electric drive, which is not possible with Honda's system. Unlike Toyota's system, VW's only requires one motor/generator instead of two, and that means one frequency-inverter instead of two (think: less $, less stuff to go wrong). VW's system also allows full mechanical drive with NONE of the power path going through the electrics (unlike Toyota) - this is better for highway driving. VW's can't act like a CVT, but with a 6-speed (or 7 speed? we don't know) DSG, this is not a big deal.
Battery pack weighs 35 kg and takes up 35 litres. I don't know where they put it. This is a bit smaller and lighter than the battery pack used by Prius. (Think $ again)
One would think that by knocking a cylinder off the engine, it'll offset some of the weight of the motor/generator, the frequency inverter, and the battery.
I really like this, and I'd consider buying one. WHEN, and HOW MUCH.
Having only one motor/generator and one frequency drive and a smaller battery pack (compared to Prius), and making use of a gearbox and engine that are more or less off the shelf should keep the extra cost under control.