Hello,
You announced working on the unmanaged window problem in September 2001 IIRC, but I guess you didn't so far? Wouldn't, for the time being, a Cedega-like approach be feasible? They seem to ignore 'chromeless' windows and handle them just like regular windows (with window decoration and all, for Steam for example) - this is obviously not correct, but it would at least work 'till someone comes up with a real fix...?
Wouldn't be much motivation for somebody to come up with a real fix if there was already a half-baked fix in Wine already, would there?
I've sent 2 patches addressing this issue to wine-devel last year. The first patch(http://www.winehq.org/pipermail/wine-patches/2005-March/016558.html) made children of the desktop managed, the other patch made WM_SYSMENU(Sorry, can't find this one in the archives) windows managed. Both patches were neighter applied nor discussed further.
My observation was that all affected windows have a WM_SYSMENU | WM_POPUP style, but do not set WM_CAPTION | WM_EX_APPWINDOW or any other styles which would make them managed. Making WM_SYSMENU windows managed fixed a few apps, like Steam, Quicktime Half-life(parts not managed, can't navigate through the menus). I didn't notice any side effects(The windows had no decoration, which is completely correct), except that Steam and QuickTime seem to provide their own window movement code which conflicts with KDEs window movement handling. So if you move a Steam window to the corner of the screen, it won't move out of the screen, but Steam expects it to and mouse clicks are placed incorrectly. Quicktime can't be moved at all. I am not sure if this the direct fault of making those windows managed, or if there are some other bugs.