I believe the AROS version of E-UAE has a similar feature, but I'm wondering if it would be possible to implement this in WinUAE.
Basically, I'm wondering if it would be possible (on a RTG desktop or otherwise) for Amiga Intuition-based windows to be displayed as draggable WinAPI windows separate from the emulated Amiga desktop. These would retain their Amiga "skin" (by not using the Windows borders), and functions such as drag and resize would be integrated appropriately with Windows API functions. The Amiga (or RTG) display itself could be in a separate minimisable window (which may or may not also contain such other windows). Finally, the windows could be either unscaled (perhaps too small) or scaled/doubled/filtered etc. as appropriately selected.
This would likely be achieved through a combination of modification to the WinUAE source, and Amiga-based integration software which is run with Workbench, and able to pass the Intuition data (via WinUAE) to WinAPI and vice versa.
From my very limited understanding of Amiga Intuition, the windows are represented as rectangular (blitted?) screen areas. I'm not sure if the windows would have to be non-overlapping on the Amiga desktop for such an integration feature to work.
Similar features are found in various virtual machines, such as Microsoft's "Windows XP Mode" on Windows 7 Professional (which includes these integration features in Windows Virtual PC). I see no reason why an emulated environment couldn't perform a similar feat.
I'm not sure if Toni has any interest in working on such a feature, however AFAIK it could potentially be implemented by anyone with enough working knowledge of Amiga Intuition, WinAPI and C/C++. However, would anyone else be interested in such a feature?
P.S. As a picture is worth a thousand words (apparently), I included a quick mock-up of what such a feature might look like. (Only the clocks would match
)