[Tim]
> If there are 3 Elders [snip]

[Łukasz Langa]
It looks like the number 3 is popular in this context. What makes it so attractive?

Likely because it was the first specific non-insane number someone mentioned.  It helps to be concrete, but I don't know that anyone is wedded to 3.
 
I see a bunch of problems with such a low number, like the ability for a single corporation to take over the design process of Python by employing just two of the three members (consistently voting over the third one).

Perhaps then you don't want a "supreme court" at all.  We've been living for decades with the possibility that a single corporation could buy off Guido.  Would it really help to change 3 to 5?  Then Evil Corp only needs to buy off 3 - but the larger the number, the more likely Evil Corp will get some votes in its favor without needing to pay.

If semi-dictators are part of the New Order at all, they need to be trusted a whole lot (although I suggested a mechanism for impeachment too).

 
3 also has high likelihood of ties if one of the members abstains.

I don't care about that.  How often did Guido abstain?  it's an Elder's _job_ to make potentially unpopular decisions.  If one abstained without extraordinarily solid reason, I'd move to impeach them - they're not doing the job in that case.

If they tied, that's fine too.  Ties favor the status quo (same as if the proposed change had been rejected).  For that reason, I'm not even wedded to an odd number.

 
And so on.

Likewise in the other direction.  For example, how many "extremely trusted" people can we even get to volunteer for a contentious, long-term, non-paying job?  I don't know.  "3" probably started with the first person here who suggested specific names and could only come up with 3 ;-)

Taking a step back, before we talk names, term limits and even numbers of council members, Python needs a "constitution" which will codify what the council is and how it functions.

"Feedback loops" - all decisions feed into each other, in all directions.  For example, the number of people on the council has real effects on what it's _possible_ for it do, and on how it functions.  It doesn't hurt to think about everything at once ;-) 

 Barry calls it PEP 2 but I'd like to understand who is supposed to author it and who is supposed to accept it.

Any committer is in a position to suggest parts of or the entirety of such a document. Otherwise we create a fractal problem of who and how decides on who shouId be writing it. Ultimately we are volunteers, the ones who step up and do the work.

 Sure!

Ideally Guido would accept the PEP but I'm not sure if he is willing to.

His initial message here seemed very clear that he wants us to "figure something out for yourselves".  He's tired of the battles, and perhaps you have to be as old as him (as I was 4 years ago) to grasp what "bone weary" really means ;-)
 
If that is indeed the case then how should this be done so that the document is universally accepted by all committers?

Perhaps it won't be - after all, much of the point to a dictator-workalike is that universal acceptance is a rare thing in real life. Guido left us with an interesting puzzle to solve :-)