The Ninja Burger "concept" has since appeared in a roleplaying game/tactical board game named Ninja Burger:The Roleplaying Game. (Oddly enough.)
The game expands the Ninja Burger mythos, with information on the various clans of the Ninja Burger corporation and the enemies of Ninja Burger: Samurai Burger, Otaku Bell, the Lo Cal Clan, a secret ninja clan that refuses to eat meat and wishes to destroy the mighty Ninja Burger empire from the inside, and OOPS, the Oni Oni Parcel Service, a package delivery company whose employees are actually powerful demons from another dimension, all of which hate Ninja.
Ninja Burger: The RPG is published by 9th Level Games, whose other notable game is Kobolds Ate My Baby!. Both of these games use 9th Level's BEER Engine, a game system so simple you can play it when drunk.