Thank you Dave, that looks great!
I have installed WindowBlinds now and tried one of the themes that come with it.
Works good, however, it seems that the skinning is not HiDPI aware?
Everything looks blurry on my 4K monitors with Windows scaling set to 200%:
Is that normal, I mean, are the skin elements of WindowBlinds (like buttons, round corners etc.) not available with HiDPI resolution?