G100UL is the answer - or will be.
If you think true 100 octane fuel going away is the answer you're NUTS.
Without it everything over 235hp goes away. No more C210s, C310s, Bonanzas, Barons, Cirrus, RVs, C185s, C195s, Warbirds - the list goes on.
Avgas high priced?
30 cents a liter more than the **** fuel you buy from the local servo is too high a price to pay for high quality 100 octane?
If you think that is what is 'killing' GA, or that 'GA' is in fact dying, you're just ignorant. In areas where its needed charter GA is doing fine - it just isn't needed in the J curve anymore.
Fuel is about 30% of the cost of running a C182, C210, Bonanza etc - if it was 30 cents cheaper/litre that might reduce to 25%. Don't get me wrong we'd all love cheaper fuel but if you think 5% is a deciding factor you're wrong.
The REAL difference in costs between a homebuilt aircraft and a GA piston 4 or 6 seater is govt maintenance regulation and red tape.
Aircraft like Jaba's RV10 cost as much to build as buying a decent 4 seater such as a F33 Bonanza. They burn just as much avgas as any piston single of comparable HP and yet RV numbers are booming. DOCs, insurance, hangarage, IFR enroute charges all very close.
Where they save is labour/maintenance. Annual maintenance costs on an RV10 are probably 10% of a C182.
Cheaper fuel would make not one bit of difference - high quality 100 octane going away would decimate GA. G100UL probably won't be much cheaper than 100LL but it should be lots easier to transport/store and THAT is where the saving is - there is so little TEL in it that there will be virtually no saving there.