Solved it myself...wasn't that hard actually!
I just used xprop to grab a window's title and then passed it to compiz's widget layer plugin through gconftool-2. This way I wouldn't be even bound to the "active nautilus" window, but any window on the screen because xprop can grab any window's title!!
a simple file like this:
then all I had to do was to assign some key bindings to the file in CompizConfig Settings Manager.
new="$(xprop WM_NAME | cut -d \" -f2)"
old="$(gconftool-2 --get /apps/compiz-1/plugins/widget/screen0/options/match)"
target=$old" | "$new
gconftool-2 --type string --set /apps/compiz-1/plugins/widget/screen0/options/match "$target"
Also added one for getting all the windows back to the normal layer with:
Worked like a charm! \.
gconftool-2 --type string --set /apps/compiz-1/plugins/widget/screen0/options/match ""