Both Guardians with Tractor Pads are in the game, somewhere in the Mountains. I can't remember the direction though.
You can craft the small and medium, just not the large. You can also craft the large Receiver and Medium Silo which, combined, I believe hold more than the large Tractor Pad plus the large Receiver allows you to pick up Blocks on the field. Combine that with the Scrapper and you've got all kinds of Resources.