While we're in a Twelfth Night frame of mind, why not see what Stephen Fry did with Marvolio in the same scene. This time, we're whisked away to the Globe Theatre (the newest one) to witness the discovery of the mysterious letter:
Notable elements here are Fry's ability to have us see what he sees, his ability to make the imagined advice to Sir Toby seem imminently reasonable, and that marvelous re-entry for the postscript. But it's hard to see Stephen Fry as being mean or malicious. The business with the hiding place is also interesting and well-executed.
Links: The Film at IMDB.