Federico, the developer of Launcher Pro, just released a music app. It's based of the Zune style player of WP7 and it's extra slick. It's still in alpha so it only has basic capabilities but it is the best replica I've seen so far. You should definitely check it out.

Federico Carnales Releases Alpha Music Application - Droid Life: A Droid Community Blog

Windows Phone 7-style music player for Android arrives from the developer of LauncherPro -- Engadget