Concept-only but still neat
https://wildmind.be/type-0-aluminium-mouse/
Ergonomically that is probably not comfortable to use, but it does look pretty neat looking.
Reminds me of the Macally Acuglide aluminum mouse (https://www.newegg.com/macally-accuglide/p/N82E16826172009), of which I might still have in the laptop bag for my PowerBook G4 12" 1.33ghz along with my first gen Magic Mouse.
Oh wow, that looks perfect for the time! Never seen that before.