Well, im going to supply my input seeing as I also have a 48" tank with a 400W halide over it and a center brace. The shadow looks bad in FTS but in reality it is not that bad. My corals are all very happy, and even light lovers are fine at the end of the tank. Here is a link with some pics:
http://www.canreef.com/phpBB2/viewtopic.php?t=18403
The halide is about 10-12" up and the centerbrace gets hot but it is still strong, it does not become softer. My tank is a 75g BTW.
I have since changed the aquascape but I'll try to get some pics. Now the shadow is even less noticeable, and event the xenia under the center brace is doing fine. I will get some pics of it if I can.
Chris