Custom Pen Flashlight?

Hi, I am looking to build a custom pen flashlight. The switch will be on-on-off. I have pics of housing and the components. The problem is the components sizes are too big for the housing. Looking for help locating smaller components and the assembly.


Picture of Custom Pen Flashlight?
20160908_101156.jpg
20160908_101225.jpg
20160908_102513.jpg
20171013_162412.jpg
20171013_162412.jpg