The gblogger GUI lives! It features listing the blogs for a user, listing the posts for a blog, new blog posting, and blog editing. Wysiwyg is achieved using GTKHTML3, and I have barely formatted this post because formatted posts seem to give 400 posting errors!
The client lacks category management, and image uploading, which remain on the TODO list.
(Now I am tentatively pressing the save button...after which I will re-edit the blog in Blogger.com, and add some screenshots!)