Deviantart member CookieMonster21x has created two sets of Windows Phone lock wallpapers based on the metro look. The two designs come in the stock accent colors of your Windows Phones (blue, red, mango, green, magenta, purple, lime, teal, brown and pink).
Each zip file will contain all ten color patterns and I'm not sure if I like the conservative version or the more colorful version two. Feel free to share which you like the best in the comments section or share your personal wallpaper favorites in this WPCentral Forum discussion.
You can find the Metro Lock Wallpapers Version One (the black background) here and Version Two (the colorful backgrounds) here.