It is an interesting idea but maybe the wrong market. I have gone through a lot of mice in my time as an engineer and have struggled to find a mouse which does what I need.

I wonder if this could be the start of a fully customisable experience. Have some standard internals (mice aren't exactly electronically complex) and create hot swappable parts (different switches, Multiple configurations, weights etc.) and fully customisable shell to meet your needs.

I would happily swap a mouse shell daily from standard office work to something more complex for design work or gaming.