This video (http://youtu.be/P2GThfvYp7U) gave me the idea. I found the GIF on Ponychan. So all I needed is to find a splashscreen engine (for Linux obviously) which can play fullscreen animations. fbsplash (http://fbsplash.alanhaggai.org) somewhat can, as it only takes MNG animations and doesn't support all MNG features.

But after all, it works, so let's see how Pinkie can make OS booting like 120% cooler.