Here is a simple splash I made for myself using a picture I found on DeviantArt.com. Unfortunately, I can't find the picture on there again. So, I'm not sure who the original author is, but I take no credit for their work. I only take credit for some small modifications, writing "amarok" on it, and making it a splash.
To use this splash, simply download the .tar file, extract it somewhere, and copy the splash_screen.jpg image to /home/your user name/.kde/share/apps/amarok/images If the "images" directory doesn't exist, simply create it.