Tonight I quickly threw together a Plymouth theme for Kubuntu. I borrowed the ubuntu-logo theme and edited it to fit Kubuntu better by changing the background colors, the color of the progress dots, and added a glowing Kubuntu logo. The logo is temporary as we await our new branding logos. As soon as we get that, we will put those in, and tweak the theme as needed.
I am aware of the clipped edges in the following screenshot, and this will be fixed in subsequent releases.