You often hear people talk about Rock and Roll Heaven and the fabulous group that must have been formed to include members like Buddy Holly, Janis Joplin, Elvis Presley, Jimi Hendrix, John Bonham and so on. But there's another celestial group whose membership increased this week...Fast Food Heaven! Gidget , a 15 year old female chihuahua was the pitchman, er, ah, pitchdog for Taco Bell until a stroke put a permanent end to her advertising career - an effect eerily similar to the one might get from the product she pitched. But health concerns aside, she becomes the latest member of that great fast food restaurant in the sky. It's no wonder Taco Bell had a dog as a spokesperson. Some of their menu items looked like they came out of the south end of a north-going mutt. But I digress. 15's pretty old in dog years. But she's not the only junk food maven to live to a ripe old age. Other elderly members of this high cholesterol collection include Ray Kroc founder of Mc