Hi, there's nice plasmoid on kde-look.org, which allows to tune the look of digital clock. Here's a simple ebuild for it. Reproducible: Always Steps to Reproduce: 1.
Created attachment 206975 [details] ebuild for adjustableclock-2.2 ebuild
Created attachment 212400 [details] reworked ebuild
Created attachment 212806 [details] New version of ebuild
In the kde overlay now as kde-misc/adjustableclock
In tree (version 2.6.1)