Go with a P-38.
I have a Wenger Waiter, which is 85mm instead of the Bantam's 84mm... it's just too big for my keys. I like a more minimalist approach. And I wanted something I could mod into my mini champ, honestly. Charles.
This old Japanese mini hobo knife has a functional can opener.
Another side note: one wonders how effective a corkscrew of that size can be...