Pretty good start I must say, I have worked on such projects myself, and this can done using GreaseMonkey or Stylists.
I see that you said you would release a script but it would be hard to update. This is not so, a friend of mine named Evening Newbs created a Greamsmoneky mini script that allows you to have a auto updater. Look into that here:
http://userscripts.org/scripts/show/20145
Some Quick Bugs:
1] On my machine my res is
1920 x 1080 and the logout/login and shortcut bar are kinda floating where ever they feel like to teh left, no biggy.
2] After you post, the "Return to thread page" is blank. No biggie again. It still auto redirects.
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Like I said, I have done my own extensions, theme mods, css altering stuff and helped with GaiaTools in the past, if you need an help, I am here. I just love this kind of stuff. I have my own user scripts if you wanna look into those. Feel free to Private Message me.