Couldn't you configure the existing panel to do what you want? Add and remove widgets and resize it and you should have what you need.
Linux
From Wikipedia, the free encyclopedia
Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
Rules
- Posts must be relevant to operating systems running the Linux kernel. GNU/Linux or otherwise.
- No misinformation
- No NSFW content
- No hate speech, bigotry, etc
Related Communities
Community icon by Alpár-Etele Méder, licensed under CC BY 3.0
No: there is no krunner widget I can add to the panel and AFAIK no way to hide/show the panel via a keyboard shortcut
As far as I'm aware, no launcher (in the style of KRunner) exists which has all those features.
With some effort, you could implement a lot of this functionality using a "generic" launcher (like rofi, for example), but integrating a system tray will be close to impossible (unless you're willing to write a program which acts as a system tray and provides those launchers with enough information to display a useful representation of the tray, could be cool).
GNOME
Edit: Sorry, I may have misunderstood the question as I'm not entirely sure what a launcher is in the context of Linux, but I've been using GNOME as my desktop environment for years and it does everything asked for here.
You can create a panel in edit mode and put whatever you need (clock, system tray, application menu) on it. Set size to fit content and make windows go below which results in a tiny floating panel for example.
AFAIK there is no krunner widget I can add to a panel... but regardless: can I have the panel show/hide via some keyboard shortcut?
(If they can't be together, I could live with alt+space => toggle krunner and, for example, alt+shift+space => toggle panel)
I'm not sure if you can show/hide like that, but as a workaround you can toggle auto-hiding with a qdbus command, and set a keyboard shortcut to run that.
IIRC krunner works as a commandline tool, so maybe you could do what you want with something like yakuake, or even make a wrapper for krunner with those additional options.
It seems like something I could use as well. I'll note it down to take a look later.