MusicBarExtended would allow you to do this. It's not a theme but more of an app/tweak which you set using Activator. Not exactly what you're looking for but might wanna check it out and see if it fits the bill.
I believe you can since it's set through Activator (I don't have it installed on my phone at the moment). I had mine set to activate only when I double tapped the status bar on the lock screen so I'm pretty sure you can set it for just the LS.