Changing the position and color would be enough for me.
It seems to work when you add references to it under 'TrackLove' like this:
<element id="TrackLove" parent="Panel">
<left relativeTo="TrackRating.Left" offset="-28" />
<top relativeTo="Panel.Bottom" offset="-24" />
<images category="NotLoved"
default="Images\LastFmNotLove.png"
highlight="Images\LastFmNotLoveBright.png"
/>
<images category="Loved"
default="Images\LastFmLove.png"
/>
<images category="Banned"
default="Images\Banned.png"
highlight="Images\BannedHighlight.png"
/>
</element>
Since a track can't both be Loved and Banned at the same time it will have the same position as 'Loved'.
The 'ban' feature doesn't seem very popular though. I just looked for the shortcut key to easily set a track to 'Banned' but it looks like it doesn't exists, nor a.f.a.i.k. has it ever been asked for.