After more than two years of wanting this
costume, we finally took some of the tax return money and purchased a Senate Guard helmet for my husband. It came a couple days ago. It will require some work, we got a "raw" helmet because it was about $100 cheaper. This way too, we can choose the color of paint to match the robes more closely. The "spine" is rather crooked, so we'll have to fix it, or create something new. The "lens" is just wrong, it should be black and a more rigid plastic, like sunglasses lenses.
The Helmet:
Front
3/4 Front
Left Side
Back
Right Side
Top
Inside
Spine side
Spine Back
Spine Front
"Lens"