just to be realistic, a 3 speed comes with 2 gear options ,
classic is 3/4 and 4/3 of the middle ratio.. .75 & 1.33
SRAM has a bit wider difference between gears 36% rather than 33%

but a 3 speed can be put in fairly narrow frames like track / single speed types.
some of the multispeed IG hubs are needing a wider axle to get it all in..

,, and do get a really good lock, so you don't have to do this again.