I know in KDE you can add multiple panels and then add widgets to those panels. But is there a way to get open windows to only display in the taskbar in the monitor that they're open in? Essentially what I'm looking for is a linux (KDE) alternative to ultramon.
Here's the procedure for KDE 4: right-click on an empty part of the taskbar, choose "Task Manager Settings" from the popup menu, and in the resulting dialog, select the "Only show tasks from the current screen" checkbox. Repeat this for each taskbar you have.
Note that if there are enough windows open to fill up the taskbar, there won't be any empty space to right-click on so you'll have to close some windows or switch to a less full virtual desktop.