I have one similar to Mark, a dart running 4 x 1" on a OM 4way. I built a fake rock enclosing an ABS "Y" fitting for the intake, and 4 holes along the bottom.
If you want to waste an hour of your life you can look at the details in my tank build here:
http://canreef.com/vbulletin/showthread.php?t=50842
My corals are growing quick, and when they get really big I might add another closed loop. I can't bring myself to putting a powerhead in my tank. The only visible piece of plumbing in my display right now is the omni flex nozzle from my wavy sea.