Kelly: I wanted to use a siphon system on my recent pond rebuild, but didn't have sufficient elevation change (below the dam) to make it work. Instead, I used a modified version of what you're talking about, utilizing 6" PVC. The top fitting on the discharge stack is not glued, so I can change elevations by simply adding or reducing height. The pond is now at pool level, and everything seems to be working just fine. I still have to pour a concrete "splash" apron below the discharge. Look toward the very end of the photos.
http://s1179.photobucket.com/albums/x398/critterville/?albumview=slideshow
