No, there's no such plugin. It also doesn't have anything to do with virtual desktops, so you could try a third party tool: https://sites.google.com/site/inactivewinfader/

hi,
I am very new user of dexpot. i like the transparency feature as well as roll-up feature here.

I want the transparency for windows being changed if the window is not active for say 30 sec. If one can track the mouse-focus, then only if mouse is on a window for 5 sec, windows should be non-transparent. it should be non-transparent when title bar is clicked , or unminimzied/restored .

is there any plugin for the same?

regards,
amit