i do have some transparent status bar mods in my mods thread. there are a few issues with it though, which may or may not have a fix:
1) depending on which launcher you use, the wallpaper may or may not bleed through like towle mentioned. for instance, with touchwiz, when displaying the home screen(s), it calculates the wallpaper height/top by subtracting the height of the status bar, so it will always be black behind the status bar with touchwiz. zeam launcher does not do this, so you will see the wallpaper behind the status bar. I have tried editing the wallpapercanvasview.smali class in the touchwiz apk so that it subtracts 0 instead of the height of the statusbar, but it has no effect. that is something i am continuing to work on.. i have a list of launchers that work the best with the mod in the thread.
2) every app deals with the status bar differently. some apps cover it completely, some apps extend a solid color all the way to the top of the screen (which would show up behind a transparent status bar) , and some apps consider the bottom of the status bar as the top of their screen (so the wallpaper would show up in this case, again depending on which launcher you use)
3) when you make the statusbar transparent, notifications can overlap making a mess up there. for example, when you pull down the notification menu, the date appears in the upper left, but the status bar icons behind the date show right through. the way i fix this in my mods is that i make the background of the date black with a kind of glowing color gradient that matches the color of the theme.
here's your custom color mod (with 50% transparency) with 50% transparency on the status bar too.. see if you like it!
BRKOTUC'S Custom clear pulldown/statusbar mod with swipe and ICS animations
let me know what you think..