After years of my desktop environment (kde) being configured the same way, I tried enabling auto-hiding in my panel and I quite like the extra screen estate.

Now, the only reasons why I have a panel in the first place are the clock and the system tray (I don't use the start applications menu and I don't care for the task manager) so I've started wondering if I could completely dispose of the panel.

Do you know of any launcher (I use krunner but switching to something else is fine) that satisfies (or can be configured to satisfy) the following?

1. shows the current date/time
2. integrates a system tray
3. launches applications
4. does math, unit conversion and currency conversion