For the most current cost estimates, see the 2010 report on German Unity projects (pdf!), where the total project costs are estimated at 5.2+2.75 billion, and the money still to spend at the end of 2009 is put at 4+1.4 billion.

Note that the 2.7 billion total for the Ebensfeld-Erfurt high-speed line itself in your link is line with the cost named in this parliamentary reply. The rest of the cost estimate includes the €0.3 billion Nürnberg-Fürth upgrade, some other works and planning, and the one part still without a financing agreement, the four-tracking and upgrading of the Fürth-Bamberg-Ebensfeld section (the 2017 finishing date is only for the Ebensfeld-Erfurt high-speed line). (The 1.95 billion total for Erfurt-Gröbers is also okay if we consider that the rest includes Leipzig-Gröbers, already in operation.) So I'd estimate that the money still to be spent on Ebensfeld-Erfurt alone is about 2 billion.

Methinks a further long delay of the Fürth-Ebensfeld section is more likely than not paying already contracted superstructure and track contractors to the extent that they stop work, or a halt in contracting trackwork; so methinks any further delay will be only a year or two.

_{*Lunatic*, n.
One whose delusions are out of fashion.}