(Yes, I know this is two days ago, but I only had time to compile it, not write this until today. I should get the latest revision later today.)
One thing that's been bothering me was that the status area buttons (battery, network, and the ~main-menu button) wouldn't change at all on mouseover. Fortunately, they do now, and they look quite nice. The third main-menu button got a redesign and is now smaller. The battery button was switched to the left of the network one. Functionally, nothing has changed.
The about dialog got an interesting change: Chromium OS draws a custom border instead of using the standard Gtk one. However, this does not seem to be the case in the normal Chromium. Speculation: all dialogs will be like this, even the about, import, clear data, bookmarks manage and edit, and several other dialogs.
Also, I fixed some things with the diff that a while ago I (for some reason) thought were necessary when they were not. There now is no option to use the standard Gtk window decoration for the main window.
Download revision 29835: Extract the chromium-os-rxxxxx.tgz archive and run chromium-os. To get the many translations, extract chromium-os-i18n-rxxxxx.tgz and move the files to the locales/ folder. To get the HTML element inspector, extract chromium-os-inspector-rxxxxx.tgz and move the inspector/ folder to the resources/ folder (create it if necessary).