A worthy suggestion, and that would put my home town safely in the "red" part. Other suggestions (the north/south variety) would just make Fresno subservient either to the Bay Area or to LA -- same as always.
However, I don't believe that California will ever be split, unless it is by a great earthquake that shakes the coastal areas into the sea.
Under my proposal, San Diego would be the largest city in "East California" (and SD County votes consistently Republican), but Fresno would probably the second largest. Sacramento would still be the capital.