Considering that Cosworth had arguably the best F1 engine in 2006 I guess that they would have a very good base to work from with the "standard" engine. I guess that's probably one of the reasons FIA picked Cosworth as the winner of the tender to build F1 engines.

Remember that the engines in F1 today are 2006 engines with frozen development and rev limiter. I seem to recall that Cosworth at the end of 2006, just as all the other engine builders, made a final version of the 2006 engine to be homologated for the 2007 season. That included the rev limit and technical spec. None of the other engines have been developed since the end of the 2006 season(supposedly...). In reality Cosworth probably could supply a very competitive F1 engine to a team even as early as next season by digging out the homologated F1 engine for the 2007 season. The Honda team is in need of a engine for next season and they are also positive to the standard engine proposal from FIA....

In reality Cosworth will maybe just have to modify their existing design slightly for the "standard F1 engine" design for the 2010 season.