Conversation so far:
What was an unfinished project of Chris Farley's?
Chris Farley was originally cast as the voice of the title character in the film Shrek, but died just before recording was finished.
Who replaced Chris Farley in the movie Shrek?
Shrek's dialogue was re-recorded by former SNL castmate Mike Myers.
What else did Chris Farley leave unfinished, besides Shrek?
Chris Farley was slated for another voice role in Dinosaur.

Question: Did he start working on that?
Self-contained rewrite: Did Chris Farley start working on the movie Dinosaur?