Emit reStructuredText from sphinx autodoc?

Not a full answer, more or less a starting point:

autodoc translates auto directives to python directives. So one can use autodoc events to get the translated python directives.

For example if you have the following mymodule.py:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
This is my module.
"""

def my_test_func(a, b=1):
    """This is my test function"""
    return a + b 

class MyClass(object):
    """This is my class"""

    def __init__(x, y='test'):
        """The init of my class"""
        self.x = float(x)
        self.y = y 

    def my_method(self, z): 
        """This is my method.

        :param z: a number
        :type z: float, int
        :returns: the sum of self.x and z
        :rtype: float
        """
        return self.x + z 

sphinx-apidoc will create

mymodule Module
===============

.. automodule:: mymodule
    :members:
    :undoc-members:
    :show-inheritance:

The following extension (or addition to conf.py):

NAMES = []
DIRECTIVES = {}

def get_rst(app, what, name, obj, options, signature,
            return_annotation):
    doc_indent = '    '
    directive_indent = ''
    if what in ['method', 'attribute']:
        doc_indent += '    '
        directive_indent += '    '
    directive = '%s.. py:%s:: %s' % (directive_indent, what, name)
    if signature:  # modules, attributes, ... don't have a signature
        directive += signature
    NAMES.append(name)
    rst = directive + '\n\n' + doc_indent + obj.__doc__ + '\n'
    DIRECTIVES[name] = rst 

def write_new_docs(app, exception):
    txt = ['My module documentation']
    txt.append('-----------------------\n')
    for name in NAMES:
        txt.append(DIRECTIVES[name])
    print '\n'.join(txt)
    with open('../doc_new/generated.rst', 'w') as outfile:
        outfile.write('\n'.join(txt))

def setup(app):
    app.connect('autodoc-process-signature', get_rst)
    app.connect('build-finished', write_new_docs)

will give you:

My module documentation
-----------------------

.. py:module:: mymodule


This is my module.


.. py:class:: mymodule.MyClass(x, y='test')

    This is my class

    .. py:method:: mymodule.MyClass.my_method(z)

        This is my method.

        :param z: a number
        :type z: float, int
        :returns: the sum of self.x and z
        :rtype: float


.. py:function:: mymodule.my_test_func(a, b=1)

    This is my test function

However as autodoc emits no event, when the translation is completed, So further processing done by autodoc has to be adapted to the docstrings here.

I had same problem and for one time generating of docs I've used quite ugly solution to patch Sphinx, see Make Sphinx generate RST class documentation from pydoc.