Thirteen (13) Justices. One Justice from the legal community in each regional court of appeals district and one from the federal circuit. The one federal circuit justice would serve as chief justice.
As one Justice leaves, they could only be replaced by someone from the vacant district.
In this theoretical model, the president still picks, but the pool is limited by circuit (and potentially culture contained in the circuit.)
My theory, the most liberal nominee from the 4th circuit is likely more conservative than the most liberal person from the 9th Circuit. Contrariwise, the most conservative person from the 9th circuit court of appeals is likely to still be more liberal than the most conservative person from the 4th circuit court of appeals.
