Version: (using KDE 4.2.96) I recently got a tablet pc and so I need an onscreen keyboard to unlock the screen for typing in my password. I suggest that as an option (disabled by default) an onscreen keyboard should be integrated into the password-dialog. It could be accessible though a small button with a keyboard icon in the bottom in the password dialog, what will extend the dialog with an onscreen keyboard in the bottom of the dialog. There is already a decent onsceen keyboard in playground (kvkbd), this could be used as an base to do this.
*** Bug 140034 has been marked as a duplicate of this bug. ***
there is a way to get this right now, though a bit more work for the user: enable "widgets on screensaver" in the screen saver configuration, and then add the virtual keyboard widget (which is now included in kdeplasma-addons! :) actually, now that i've said that i'm not sure how well it will work given that the screen unlock dialog isn't a managed window .. it may or may not work; if it doesn't then a bit more work would need to be done there indeed.
*** This bug has been marked as a duplicate of bug 181554 ***