Informative panel, tied to title / to the class of a window

[kalpana]

Does someone saw or does one have ideas how to realize a 1-line panel,
i.e. line of 25 pixels in hight and with different width
so that it appeared on the screen
when a window with the certain title or class appears.

In the panel it would be desirable to show information,
for example, the load of processor.
Or a button for a program launch.