I might just wire two slide switches like this (2 position switches):
**broken link removed**
To save confusion I will explain what I am doing.
I am overclocking a Nintendo 64.
A is pin 112 on the N64's CPU
B is pin 116 on the N64's CPU
1 is ground
2 is 3.3v
When put in the combinations shown in my OP the N64 works like this:
Position 1 (A=GND, B=GND): 100% - normal speed for the chip
Position 2 (A=3.3v, B=GND): 150% - normal speed for the N64 (the N64 defaulty runs overclocked)
Position 3 (A=GND, B=3.3v): 200%
Position 4 (A=3.3v, B=3.3v): 300%
So actually I made a mistake in my first post. Position 1 is not needed (underclocking normal N64 functionality), positions 2 and 3 are critical, position 4 is helpful, but most games crash on startup.