Nice idea to make a Amiga theme.

But have you ever seen a real Amiga Workbench (the desktop of AmigaOS) screenshot?

Take a look at my homepage to see some screenshots from a real Amiga:

http://www.norman-interactive.com/Amiga-Stuff.html

I fixed the shade glitch. And I also fixed the menu icon to look better.
The new version has been posted and I'm just waiting for it to be published.

And another tip:
To get the most Amiga-like feel you can change the button layout using gconf-editor.
Just open "/apps/metacity/general" in the tree menu. Now click on "button_layout" in the list to the right. Write "close:minimize,maximize".
Now you will get the close button to the left of the title and minimize and maximize to the right. To set it back write "menu:minimize,maximize,close".

I like it though I never used amigas much.
There are small glitches under buttons when windows are shaded.

Oh and I think unfocused windows should have a thin border in a color other than the background.