Steve, I really like the dual hoop style. I am going to see if I can design something that follows the contour of my high-back seats.
However, you have left out one MAJOR issue:
With ANY roll bar you need to make sure that your head can not come in direct contact with the bar! Padding the bar helps somewhat, but it is meant to protect your helmeted head and not on open head, so you can still suffer a serious injury. Plus, IMO, the padding does not look very attractive.
That leaves the high head support seats as the only safe way of implementing a roll bar (as shown in Steve's photos)! I can see how many people might object to it, as is has major impact on car's appearance (as does the roll bar, might I add [;)] ). But it would be a shame to spent the money on your roll bar and make your MORE dangerous than it was before...
Another alternative might be to make high enough to clear over your head, but would just look hideous [:D]
Every TR7 bar with factory seats that I have seen, still leaves you venerable to a head injury from the slightest of rear end collusions.
Leon
'94 Eagle Talon AWD Turbo 613whp <powered by Mitsu 4G63T
'80 TR7 Spyder GS-T <undergoing Mitsu 4G63T transplant
http://www.cardomain.com/ride/2472999