From February issue of Motor Trend:
"Next generation of Epsilon cars will use a reengineered version of the current platform. Provisional timing is 2008 Opel Vectra, 2009 Saab 9-5, 2010 Saab 9-3, 2011 Chevy Malibu/Pontiac G6, and 2012 Saturn Aura and Cadillac BLS and a Holden version for the first time.
An internal battle is going on to determine whether the Saab 9-5 or Opel Vectra will be launched first
The basic platform development is being done at GM’sTech Center in Russelsheim, Germany, and the ability to build any Epsilon variant in any GM plant tooled up to build an Epsilon-platformed vehicle worldwide is a key goal of the program. Currently, U.S. and European Epsilon vehicles aren't interchangeable.
The new Epsilons are far bigger cars than the current generation, (sources say). Weight could already be a problem, especially with AWD:The bigger cars (of which the Saab 9-5) are well over target, and engineers are trying frantically to pull them down.
As with the current Epsilon, a variety of wheelbases will be offered, but track and overhangs are also flexible this time. This allows big cars such as the Saab 9-5 and wagon versions of the smaller ones. The body design is said to be flexible across brands: Of the external skin, only the tumblehome angle is fixed, while all sheetmetal can be widely varied for each nameplate. Engines include the new global 2.8 to 3.6-liter V-6 in naturally aspirated and turbo forms. The turbo 2.8 is already being rolled out in the current-generation Saab, Opel, and Caddy, and later on the Cadillac is likely to get a 3.6-liter turbo of 340 horses.
The global toolkit includes FWD, AWD, five- and six-speed manual transmissions, and five and six-speed autos. More powerful cars such as the Saab 9-5 will be AWD for most of the range. The more premium versions including Saab and Cadillac will use aluminum-intensive suspensions."