Look at the top emblem on this guys gamertag, I have seen loads of these and i am wondering how to do it.
There is a way to do this. I watched a video of it on YouTube, but I can't find it again, to show you. Basically, you take an emblem that resembles a bar, then bring it off to the right, or left, of the editor, and after you save it, it causes the colored bars, like you can see in the picture you posted.
I'm going to try to find it again for you. I'll be back in a few minutes.