If you want to get even smaller, another option would be to convert a small twisty into an electronic sideswitch light.
You could use the same technique I used on my Aleto N8 Modding the Aleto N8
With the Aleto, I converted a light that normally has a tailcap clicky switch into one with an electronic sideswitch.
You might be able to use the same technique to convert other lights, like a 4-sevens mini 123.