I don't have decent photos yet and I haven't hung it on the sunlifts ... it's perched on my tank and I'm avoiding it until the spray paint smell doesn't make me sick anymore. BUT... I posted a 3D model of it in my gallery:
Since I'm still not sure how high I want to hang it and how much difference in height I want the halide and T5's to have, I made the hood 12" tall. It could easily fit in 6 inches though. I kind of like it being taller than needed - I think the light won't shine in your eyes when suspended this way. I'm leaving the top open so I can have some spill-over ceiling shimmer ;-)
My tank doesn't have the center bar but I tried putting a piece of wood in there just now and I could see a bit of a shadow but it wasn't a big deal. My halide is 8" above the water, there'll be less of a shadow the higher you go. I'm sure it will be less annoying than putting the light to the side. I wonder if you could replace the bar with a piece of glass or acrylic (whichever your tank is).
About halide height - there's two reasons you'd care about the height -
1) The light spreads out more the higher it is and that's an issue in situations like ours where we want it to cover 36" instead of the usual 24" per light.
2) Heat. I only have a 150w so nothing I do causes heat issues but you might if you kept it close to the surface or enclosed.
I like how mine looks at 8".
I'm sure there's better ways of constructing it (like aluminum!) but what I did was make a frame with 1x2" boards and attached birch paneling. With the lights (including the T5 ballast) it came out to 19lb. One pair of Sunlifts is rated at 22lb I think.
If you're in South Tampa feel free to come have a look =)