Among the "new threads" you can give Eddie in the Hammer of Fate DLC is a bearded look that effectively makes him Tim Schafer.
Game:
Brütal Legend
The Hammer of Infinite Fate DLC adds Mount Rockmore effigies in the shape of Razputin from Psychonauts and Tim Schafer himself.
Game:
Brütal Legend
In the opening cutscene, the Kabbage Boy lead singer performs the Bobby Zilch dance from Psychonauts when he climbs above the stage. This character is also voiced by Richard Steven Horvitz, who pays Razputin in Psychonauts.
Game:
Brütal Legend