Jerome,
Can your freind a bend partial ellipse? I have designed a roll bar hoop that follows the contour/shape of the windshield and body. I thought the roll bars out there were too square looking so I came up with one that flows with the shape. The hoop resembles a horseshoe shape.I haven't had any success trying to hot bend tubing around a wood template to make this roll bar. I have searched high and low to find a fabricator that can bend this shape. Either it is too expensive to tool up for or to much $$$. I'll share the design plan if your buddy will bend two hoops. I would pay for the material.
I was planning to make one , primarly for show yet removable. My kids love to sit in the back seat and its not wise to have it in the car when they are back there.It could cause severe head trama to them if an accident occurred. You may also concider a screen of some sort to break up the air flow turbulance around the bar. Roll bars tend to make your neck get chilled. Look at the Boxster, BMW etc. they have them.
Joe Soltis