I converted some animated gifs into qube flavored plymouth boot graphics.
https://github.com/renehoj/qubes-plymouth-themes
The readme in repo explain how to install a plymouth theme, and how to revert to the original Qubes OS theme.
The themes are most likely not going to work with AEM
qubes-theme-ani-01
qubes-theme-ani-02
qubes-theme-ani-03
qubes-theme-ani-04