I think that this tool is very nice and useful. You can find it here: http://kde-apps.org/content/show.php?content=30372 I would like having that in portage.
This thing is more dead than a cat flattened by a 30 tons truck. ;-) It's not even on the author's website anymore. Furthermore, the yakuake author told me the following about it: "The script there is a hack specific to the bash shell, and only works with certain commands. A generic, robust solution is actually quite a challenge." The good news is, though, a clean solution will be part of KDE4 and yakuake will re-use it.