Is there a way to find the email address for a specific case? I have a user who wants to FORWARD unrelated emails into an existing case without creating a new case. Ideas?

create a saved search to find the emails related to the case record?

Hmmmm....let me they that. However, when I look at the emails in the UI, the addy does not show.

hmm.. im not totally sure i understand your use case but a search should get this.. if you want to look up by case then make the case search. if you want to look up on who emails were sent to use a message search

Send an email to yourself from the case and see the address that sent it to you.