@ecomodded: Oh, offcourse! I didn´t think about diesels... I have seen one with a small belt-driven vacuum pump for an ordinary vacuum servo. I guess such a pump could be modified to be driven by an electric motor and it will only need to be activated when the engine is turned off and the servo is running out of vacuum.
But I would personally try a vacuum tank first. I guess it doesn´t need to be particulary big to give margin for several safe brakings.
Talking about preassure/vacuum, long ago they used compressed air to start diesels and gunpowder to start airplane engines but I guess none of those methods would be suitable for P&G eco-driving...
