Check out some of this guys builds. He has some very cool ideas on hiding CLs and power heads.
http://www.aquariumpros.ca/forums/fo...play.php?f=140
you can also use something like this
http://www.jlaquatics.com/phpstore/s..._ID=tz-ztsrock
just remember that the power cord will probably be visible when it leaves the tank.
HTH
Kevin