The vehicle will be a five-seater. Unlike Volt or Karma, it will not count on the help of a combustion engine to have its range extended. All power will come from the car's batteries, what may represent a range not bigger than 350 km. This is how much Tesla Roadster can run on a single full charge.
Model S's range could be bigger, if top speed was limited to, let's say, 160 km/h. Anyway, Model S will surely be heavier than Roadster, what will affect the distance the car will be able to run.
Tesla expects a US$ 400 million loan from the US Department of Energy in order to build a factory for Model S in the USA and develop its sedan. If everything goes fine with that, we may be able to see the production version ready by 2011.
Source: Tesla via Autoblog Green