When browsing the filesystem with Konqueror, you sometimes find a file you need to edit or delete, but you can't, because it's owned by root (or another user). So, the usual workaround ist to press F4, and use su and the command line.
My proposal ist to add an extra button or menu entry to Konqueror, which allows you to "switch" to another user, or to root.
To the Implementation: As far as I know, it's technically not possible for a process to gain rights, but only to start as root (setuid root), and then to switch to a less privileged user. (That's what kdm, su etc. do) So, what we would have to do is to remeber the password the user gave us, and do all file operations through some kind of wrapper script, until the user switches back.
Note: There should be some kind of visual feedback that Konqueror is running with extended rights, so that the user doesn't mix up the windows and accidently do something harmfull. My idea is to color the title bar differently, but this would require larger changes to kwin. (I'm going to post this as an extra idea.) Alternatively, there could also be an indicator e.g. in the toolbar.
PS: Please excuse the german text in the picture :-)