From that starting point, we can expect the body to be widened some to accomodate an engine larger in displacement but somewhat lower-revving than the current F1-spec V8s. The smart money would be on a less extreme and less fragile aerodynamic package than used in F1.
The news follows hot on the heels of the announcement that Ferrari will be providing the engines and have input into the design of the car which will be used by every national team on the grid starting with the 2008-2009 season, but suggests that, while the cars themselves won't be built in Maranello, Ferrari's design input will be considerably more hands-on than suggested by the original announcement.
Ferrari will also have similar involvement in the design and propulsion of an additional spec open-wheeler for the simultaneously-announced second-tier A2GP series, whose formation isn't expected for another few years.
Homologated road cars like the 575 GTC and F430 GT2 notwithstanding, the last time Ferrari turned out a purpose-built race car for anything outside its own Formula One effort was the 333SP, an open-cockpit racer that competed heavily in the late 90s in IMSA and Le Mans-class motorsports.
Anyone who isn't excited by the prospect of seeing the United Nations going wheel to wheel in purpose-built Ferrari race cars might want to have their pulse checked at this time.