> Conflict resolution takes a lot of time
> and I can't afford maintaining a separate copy of Python checkout for
> every patch

Then try various hg features such as named branches, or bookmarks, or mq, or pbranch, etc.
(or any SVN-facing tool you would like, including git-svn, bzr-svn, etc.)

> To be a maintainer I need:
[snip]

Most people in most open source projects seem perfectly content without such an artillery of sophisticated tools/gadgets. While the workflow can always be improved, it is not obvious to me that your requirements are in any way reasonable, or even serious ("serious" as in "this is the only reasonable way one can work efficiently on Python" -- plenty of people, almost all of them unpaid volunteers, seem to disagree).

By the way, the first thing needed to qualify as a maintainer would be to *prove* that you are up to the task. Not to have a bunch of nifty tools. In other words, you can't just come and say "hey, I'd like to be a maintainer" and expect this request to be granted automatically.