I would love to see a clock (or any plasmoid) that could be fairly transparent and stay above all the windows, even ones that are active. This would allow someone to easily keep track of the time while still using all available screen real estate. Currently in order to have the time show all the time, a panel must always be visible that will shrink the visible window size down by the size of the panel, even if only the small clock in the corner is desired. An auto-hide panel can be used, but that requires the mouse to stay over the panel in order to keep it shown, and of course it disappears when the mouse is needed for interaction in the active window. As a work around, a panel can be created to stay on top and contain just a clock, but this will show a panels border and not just a clock and the only way the opacity can be set is by editing the theme which then changes the opacity on everything in the theme and not just the clock. It would seem that the adjustable opacity option is the main missing feature do to the fact that a panel can already be set to stay on top, I would imagine that can easily be changed to just an individual plasmoid option.
Thanks,
Mike E.
P.S. I hate to bring this up, but M$ Windows does allow this to be done.