You could do two big pillars like on my tank and put the extra rock in the sump.
<a href="http://s616.photobucket.com/albums/tt245/jk73sb/?action=view¤t=Picture056-1.jpg" target="_blank"><img src="http://i616.photobucket.com/albums/tt245/jk73sb/Picture056-1.jpg" border="0" alt="Photobucket"></a>
haha ! i should huh.. that piece on the right side is really big.. the rocks wont need lights right?