EDIT: v0.9 released
and a dark version
I really just put a bunch of pieces together. Forked from Reactionary Plus, but swapped out the icons, cursors, window decorations, color scheme, and made some slight tweaks to the layout.
More screenshots and changelogs here: https://store.kde.org/p/2330858
To install this, open System Settings, go to Colors & Themes -> Global Theme. In the top right there's a button for "Get New...", wait for it to load (it's very slow) then search for reactionary, and wait again, then install Reactionary 98.
This is my first time messing with any of this stuff, it was a bit janky lol.
In edit mode when changing the location of the bar there should be an option for "fit content" under height Example: (sorry about the moire pattern, low res screen)
collapsed inline media
Sorry, I mean the thing where application icons grow as your cursor passes over them.
OH! I actually don't think that's possible without some kludging.
You could make a panel for each icon, have them side by side, and use Panel Colorizer to make them grow on hover, but that's mega-tedious. Totally doable though. I'd hate to see plasma's ram requirements with like 9 panels each being monitored for activity though, I suspect the performance on that setup would be rough.