I don't have my Xbox 360 anymore, but I have heard of MyGamerCard. This is a service that offers a custom image based version of your Gamertag. Now they are working on a similar service for the Zune Cards. Really a neat item since not all forums allow for flash in your signature.

MGC has released an image-based Zune Card as a small beta to preclude a new site, MZC (bet you can't guess what that stands for!)

With our Zune Card, we look nearly the same as the official Flash version, but with our signature flair that you've come to expect from MGC. Artist names are displayed underneath the album images, and the last three songs are populated in the upper corner. Images are updated every 30 minutes, for those with active listening habits.

Source : MyGamerCard via Generation Zune