So you consider Xnest and VNC hacks, but Wine's desktop mode OK?!? This is very strange, in the Unix spirit I would have thought those are the right approach for what you want to accomplish (pseudo-virtual machine).
Well, I said 'hacks' because for VNC it's not really what it was meant to do (except, of course, if one would write a VNC-protocol driver for Wine to be able to connect directly to a VNC server). This is less true for Xnest, but it is relatively unacceptable for performance reasons (for one, you add yet another process that needs to be scheduled in the equation plus it certainly will never run OpenGL in direct rendering mode).
Basically, you mean that you consider Tabbed browsing in Mozilla a 'hack' too because it should be your WM's job to do that for you ?
P.S. And no, there is no reason for WDE to be restricted to Windows apps only.
But I would want it to be. I do not want to change WM for my Linux applications, only for my Windows one. I do *NOT* want *ANY* integration between the Windows application run with Wine and my Linux applications (so I may be completely at odds with what CodeWeavers is trying to do, but oh well, I am used to have strange ideas :-) ).
Lionel