I just discovered a trick that might help:
While you are in whatever app you happen to be in, do an Exposé/Show Desktop. Now click on the desktop, which activates the Finder, and with no Finder windows open, do Exposé/Application Windows. Now you can do whatever you want (except use Exposé) and the windows rolled up on your screen edges will stay there. To get those rolled up windows back where you can use them, just use Exposé again.
I have Exposé/Application Windows set to my middle mouse button and it works great
