The test with ethanol involved a modified 2.0 T engine. Using an E85 powertrain and the biofuel, emissions were qualified as "75% better" than from the gasoline counterpart. The 2.0 T belongs to a new series of TFSI engines (codenamed EA 888) and it was rated at 210 HP and good for 31 mpg. With the Start/Stop features, the test mule managed to get 40 mpg. The mule included features such as regenerative braking and a more powerful alternator to shut down the engine at stops.
It's still unclear if E85 versions of the A5 will hit the showrooms anytime soon, although features from the Start/Stop versions might see the light. If this happened, it would be for 2009 models.
[Source: Fourtitude via Germancarblog (h/t to Christian for the tip)]