I hope somebody will find this Python script useful. I actually used this Python script to test things out first (and make sure that everything works) before I started work on fixing RavenPlus last year. I can't remember now, but I think the gist of this script came off from b.py - a Python script for posting blog posts to Blogger and Wordpress.
To post to your blog from this script, remember to replace the blogID "1087XXX5764091XXX95" in the line
post = service.posts().insert(blogId="1087XXX5764091XXX95", body=body, isDraft=False).execute(credentials.authorize(Http()))
with your blog's blogID.
To update an existing blog post, just replace the line above with the following (NOTE: you will need to find out what your blog post postID is, otherwise the statement will fail):
post = service.posts().update(blogId="1087XXX5764091XXX95", postId="4781959859649019078", body=body, publish=True).execute(credentials.authorize(Http()))
The OAuth2 login credentials is named 'plus.dat' and it must be located in the same directory as this Python script file.
I ran this script file under Python 2.4 with some customisation made to the Google API Python Client Library Version 1.2.
The Source Code