Team 3824 in our region prints their entire chassis. Oak Ridge National Laboratories has been sort of a pioneer in large scale additive manufacturing, and 3824 gets to work out of their facility with a lot of mentor support. You can read about them in the book that came with kickoff kits last year (Behind the Design). Here's a video of them printing in 2014:
https://www.youtube.com/watch?v=dvLxsRnA0Y0