media center has been removed due to copy right issues- if you really feel up to it (there are ALOT of png's that would need to be edited), then get yourself the KC_Juggalo skin (that skin has all the png files separately). Skinning is alot more involved than with other apps, the png's (xbmc can either work individual png's in the media folder, though making an xpr will reduce the skin size and improve loading of the skin) need to correspond to the name used in the invidual skin xml's which control the size, positioning, text and what (if any) alternate image is used when an icon is actually hoglighted
A skinning engine is on its way but as you can appreciate, it is a hell of alot more complicated than an evox or avalaunch skinner.