While I have seen the ATARI 2600 do this several times to save on space, it's a shame that PICO-8 does not have a scaling function for the default 3x5 font. In the original Haunted House or "Mildew's Manor" game, I made use of this double-size method in the menu.
Here now you can have it to use in your own code. See demo enclosed.
HOPE THIS HELPS !