Maybe you can use this application for inspiration: http://kde-apps.org/content/show.php/Nepoogle?content=145505

I hope you'll share your plasmoid when it's in a working state!

With best regards,
Hans Chen

On Tue, Feb 21, 2012 at 15:24, T.C. Hollingsworth <tchollingsworth@gmail.com> wrote:
On Tue, Feb 21, 2012 at 5:57 AM, todd rme <toddrme2178@gmail.com> wrote:
> There is already a krunner plugin that provides a permanent input
> field on the desktop or a panel.  However, it is not available from
> standard KDE packages, it is only on kde-look.org (although some
> distros do offer packages for it).  It may be possible to get such a
> widget included in plasma-addons.
>
> There may be ways within krunner to limit individual krunner
> interfaces to one runner, or to setup the initial configuration that
> way.

There is:
http://aseigo.blogspot.com/2011/05/krunner-doing-just-one-thing.html

-T.C.