I doubt diesel fuel is the future of general aviation - diesel engines yes, diesel fuel no...
I recall from somewhere that 99.5% of all sold aviation fuel is kerosine (of which Jet A-1 is probably the most common) and since most aircraft takeoff from airfields and not roads I don't see practical use of diesel. Also, why would you need to have two type of fuel trucks, if all (diesel and turbine) engines use same type of fuel (Jet A-1)?
Also, diesel fuel has very obvious problems with low temperatures (in C172 POH supplement it says that fuel temperature before takeoff has to be above 0°C and in flight above or equal -5°C). That would make aircraft pretty useless in those nice sunny winter days with temperatures around -15°C and unlimited visibility.
And over here, benefit doesn't justify of selling diesel fuel at airports - diesel fuel is almost 1.20€ and Jet A-1 1.30€ (tax inc.).