Splitting California into six states would require the approval of the US congress, something which is not likely to happen. On the other hand, Texas was admitted to the Union in 1845 by an act of Congress which allowed the state to split into as many as five states. There were in fact two attempts to split off areas of Texas, one to create a state of Lincoln in 1869 (comprised of the area south and west of Texas’ Colorado River) and in 1915 the State of Jefferson, from the Panhandle.
Obviously, neither attempt succeeded. Opponents argued that any split would still require Congressional approval, while divisionists countered that the 1845 act admitting Texas amounted to a pre-approval.
According to wiki, divisionism is today considered something of a fringe movement. However, the thought of eight more Texas senators is certainly more appealing than that of ten more California senators.