Here's a patch (against py3k) generated from the current state of the 
py3k-issue1717 branch, for ease of review and testing.

The patch needs serious review;  it should be considered a first draft, 
and there are probably many more changes still to be made.  I don't 
think I can do much more for now without getting input from others.

Known places in the source tree where cmp/__cmp__ still lingers on:

Demos/<many>
Doc/extending/newtypes.rst
Misc/cheatsheet
Misc/python-mode.el
Misc/Vim/python.vim
Parser/spark.py   # (I don't know what this does.  Anyone?)
Tools/<various>   # (notably pynche and pybench)

Apart from the newtypes.rst, all of the above files are somewhat out of 
date in other ways.  In my opinion it's only the doc fixes that stop the 
patch from being complete enough.