are you looking at 60 inputs?
or 60 outputs?
To control switches. That does sound like output. There are input shift registers too, and bi-directional ones and port expanders if you want to get fancy. There are even PWM output shift registers.
Tuft, KenF outlined just what I was thinking. Keep your switch states as bits in a byte array and when you change any, write the lot out through SPI and when you set the latch, the pins will all update at once. If a pin is given the same state as before, it won't change at all.
What could slow this down is changing a lot of pins through complex processes (especially if floating point is used) to which the general answer is to find a better way as there usually is at least one.
You can always get less performance and always use more code. The trick is to get more from less.