It's possible to drive all servos arranged in a multiplexed 33 x 33 grid at an update rate of 15Hz, or a 16 x 64 grid with a 31Hz update rate. In the first setup, you'd need to control 66 outputs; in the second setup, you'd need to control 80 outputs (which can be done using strings of shift registers: 9 SR for the former or 10 SRs for the latter config.). To allow the servos to be driven from the matrix, a decoder like the one shown in the attached diagram would be fitted on every servo (RSEL is active high, CSEL is active low).
This setup allows multiple levels to be sent to the servos; not just 0 / 180 degree.