Supposedly the Commission (Syndicate board previously) rules prohibit the unauthorized removal or murder of a boss. Only the Commission can sanction such actions on pain on death.

However it looks like there's only been a few cases where the Commission either took action to get rid of a boss or carried out punishment against mobsters who got rid of their own boss.

Genovese ordered the murder and later demotion of his boss Costello. No one called Genovese on this. Anastasia got rid of his bosses the Mangano brothers and faced no Commission punishment. Gambino got rid of Anastasia; it's unclear as to whether he had formal or even informal Commission approval.
And of course Gotti got rid of Castellano without formal Commission approval. The other powerful Family on the board, the Genoveses was largely unaware of the plot. Certainly the Genovese boss did not sanction Gotti's action.

The only cases I'm aware of where there seem to have been either Commission pre-approval of the removal of a boss OR Commission revenge for an unauthorized removal of a boss were in the Commission approved hit of Carmine Galante (I know that now some people say he was just a captain but he certainly THOUGHT he was the boss), the Syndicate approval for removal of Siegel, and then the Commission approval for murder of Tony Bananas for his unsanctioned hit on Bruno. (Bananas thought he had approval but foolishly didn't doublecheck his sources ).

So the question is, if you are a strong enough Mafiosi, is the Commission just a paper tiger? It wouldn't be fear of the Commission that would prevent you from whacking your boss so much as it might be fear of your boss.

Are there other cases where the Commission has given thumbs down to a particular boss or exacted bloody revenge on anyone ambitious enough to give his boss a sudden and permanent retirement?

You have to remember that the Commision is comprised of boses who are looking out for their own interests more than they are for LCN as a whole. Most of the hits you mentioned had informal approval prior to the hit teams making their move. I have to think that if it comes down to the Bosses putting themselves in harms way, via indictments for a hit that has nothing to do with their family or money, or just peacefully working with the new boss, they are going to work with whoever is in charge. Throughout history the commision has played more of a mediator in disputes (most times only when the disputes brought unwanted exposure to press or law enforcement and potentially cost them money). I guess you could say that the commision is somewhat a paper tiger, although not one i'd like to get in a cage with.

The myth that the Commission has "rules" is deeply ingrained in Mob buffs' imagination. Charlie Luciano's genius in forming the Commission was that he recognized that Mob bosses only have two things in common: greed, and distrust of each other. He never expected that the Commission would manage "the Mafia" as a whole, or tell Dons or families what to do. Instead, he recognized that the Dons who sat on the Commission would act only when they saw specific actions as being in their self-interest, and agreedto abide by decisions. If not, no decisions--and no "rules."

So, for example, Luciano tried to dissuade Dutch Shultz from killing special prosecutor Thomas E. Dewey. When Shultz refused, Luciano convinced the Commission that their interests would be endangered if Shultz carried through--and they agreed that Shultz should be whacked (and they paid Murder Inc. to carry out the hit). Ditto Bugsy Siegel's murder (probably). But after Luciano's exile from America and ouster from Cuba, his influence waned. Later Commissions lost clout because they lacked a leader of Luciano's force.

Case in point: after Profaci capo Joe Columbo ratted out a plot by Bonanno and Joe Magliocco to whack Tommy Lucchese and Carlo Gambino, the Commission called both plotters to account for themselves. Magliocco complied because he agreed to comply: he was terminally ill with heart disease and was tired of Mob life. The Commission ordered him to step down in favor of Columbo and to pay a $50k indemnity, and he agreed. Joe Bonanno refused to come in. The Commission selected Gaspar DiGregorio as his successor. Neither Bonanno nor about half of his family accepted, setting off a long, destructive war that disabled the family for nearly 30 years. Bonanno eventually stepped down, but so did DiGregorio. The Commission lost. They finally agreed to recognize Rusty Rastelli and to permit Caarmine Galante to be whacked only because he threatened Carlo Gambino. And they refused to allow Rastelli to retake the Bonanno seat on the Commission.

Another point: the Commission can "rule" when the "books" for making new family members can be opened or closed. The self interest is that distrust of each other means they want to keep families from getting stronger than the others. Families get around that "rule" simply by adding associates--technically unmade, but still earning, muscling, killing for their Dons. And,as Lilo pointed out, the Commission's "rule" about requiring approval before removing or whacking a boss didn't apply to the removals of Mangano, Costello, Anastasia and Castellano. Those events were simply faites-accompli. Some rules.

Excuse me?

I thought the main reason for Galante's hit was because he ordered the murders of the 8 Genovese soldiers/associates who muscled in on his heroin racket.

Rusty Rastelli was the nominal boss of the Bonannos. Galante got out of prison at about the same time that Rastelli went in for extortion. That was an internal struggle that was not a concern of the Commission. Galante angered the Commission in two ways: First, he openly bragged that he would make Carlo Gambino "sh*t in the street, and after Gambino's death, openly declared that he would become the new "boss of bosses." Second, he created a monopoly on importing heroin to the US from Sicily and refused to let the other borgatas share in it.

so it wasn't for the 8 murders?

Selwyn Raab's "The Five Families," which is my source, makes no mention of the eight murders.

Galante refused to let others enter the Heroin trade or Galante refusing to share some of his profits?

I would have thought that an exclusively Bonanno venture had nothing to do with the Gambinos.

I.E: For example, my gang - A sold drugs and gang B were bigger and stronger, I wouldn't pay gang B a penny. Anyway, the UK gang rules are different from the US rules. You wouldn't get a Manchester group paying to a London one.