Exhibit 1.1 is a huge step forward in terms of admin UI.
1.1 adds image upload/delete, directory creation/deletion, zip-file upload extraction, individual thumbnail creation, optional user-based image directories, and no post edit page reloads. I've fixed a bunch of stuff, too, including some umask/chmod stuff (crosses fingers), the annoying untiled floating issue, and the images appearing under the sidebar in IE.
Everything validates as valid XHTML, both on the published side and the admin side, and all of the features of Exhibit that you've come to cherish remain in there.
I moved the installation instructions into a new readme file that should explain enough to get you going. Feel free to ask questions here, though I'll be gone over the weekend on a trip to D.C. (Darn, no Philly WP meetup for me. :( )