Right now, it seems impossible to have more than one panel at the same time. Plasma's panels are nice, it's possible to add as many as you want on any screen, move them around and configure them to display only tasks from the current screen.
it's doable. Unfortunately there is no GUI config for it. You can start more panels with different configurations.
configuration (context menu): taskmanager contains option "Window List Content" (show windows from current desktop/show windows from all desktops).
panel moving (context menu): you can move panels over screens there (unfortunately currently only horizontal orientation is allowed).
What's the update on this?
That's been fixed. Awesome! Thanks.