I'm not sure if this was posted already, but I think it would be awesome if eBlah has inline moderation in posts!
Also, is it possible to make it so that posts by the author will have an image to mark that s/he posted in it?

In-line moderation? If you mean deleting / modifying or editing a particular post you can, at the top right of the posts, next to "report to moderator". or for the entire thread, the controls for splitting, deleting, moving etc.. are in the box at the bottom for moderators and admins.

About the image, you can set an image for the thread. Or have their personal image in their signature, but not sure exactly what you mean by that..