The inline comment form is currently available through Blogger in Draft. To activate this, go to Settings>Comments in your Blogger dashboard and scroll down to "Comment form placement" where you can check the radio setting for "Embedded below post".
There is only one problem with this at the moment: those of us who have customized our templates cannot currently use this feature. This is because our templates do not contain the code required to display the comment form. If you use a default template, your comment form should automatically appear below your post once you have changed the comment settings in your blog.