Unfortunately not! I have tried a few different approaches and all of them have proven in-effective.
Looking at the source code, it looks like the BlogEntry class is supposed to have the current logged in user pre-populated in the Author field, but for some reason that doesn't seem to work.
The only other thing I could think that you could do would be to generate a dropdown of all members (possibly filtered by a group, say 'blog-editors') and replace the existing author field with that.
Mo