Believe it or not, I wasn't really trying to make it exactly like iTunes' Mini Player (other than the Close/Min/Zoom buttons);
I was just trying to preserve the current layout (e.g., Volume slider under Prev/Play/Next, Repeat and Shuffle on the right).
I know no title bar is a HIG no-no; it was mainly to try to minimize the space the window would take, which is the whole point of a "Mini Mode".
(One thing though: since in Leopard, all windows will be "unified", the line between the title bar and the rest of the window will kind of be blurred, so... is the clearcut presence of a title bar still absolutely necessary?)
OK then, if you want to keep the title bar, is it at least possible to make it a smaller title bar, like palette-type windows' title bar?