I see no one responded to your question so I'll take a shot.
I believe the only retina compatible skin is the default Noire skin so the skin options right now are pretty limited. The good news is the skin can be tweaked. Like you, I wasn't a big fan of the standard skin so I modified it a bit and you're welcome to try my modified version.
Here's where I posted it. Check post 6 for the download link. Post 10 explains where to put the skin files.
http://yabb.jriver.com/interact/index.php?topic=85958.0If you want to modify the text color of the currently playing track, you can do this by editing the main.xml file with a text editor. The wiki explains this but not in great detail. Look in the main.xml file for the code section called "List". Here you can change the hex color codes for the currently playing text. For example you could change the color to red so it stands out more.
One key thing to remember is that when you update Media Center, it will overwrite these modified files so you need to keep a copy of them and manually copy them back in place each time you update.
Good luck.