I'm cautiously optimistic about this seat. Don't know if I'll ever cough up the cash for it, but I can also say that if it was on the market right now, there's a 99% possibility I would purchase it. (I have two children who share a spot with me -- literally, in the case of my vehicle. The best plan of action ends up being reinstalling on a daily basis.)
If they popped up the upper harness height by an inch or two, then I would definitely buy it.
The 35lb weight doesn't bother me too much -- although I'm assuming it's because the base is solid/heavy, not necessarily the body of the seat. That makes me a lot more comfortable using the base. I mean, would I trust my 65lb child to a SR22 base? Of course not. But to a base that's built like a Radian? I'd be a lot more inclined to take that leap of faith. So if the seat weighs as much as the Nautilus, and the base is heavy on top of it, 35lbs doesn't surprise me.
Even if this seat itself doesn't turn out to be the best thing since sliced bread, Graco still gets points for innovation. It's maybe the first truly new idea I can recall seeing since I've been here, aside from Britax' slideguard.
The seat's still in prototype, I know -- given that they plan to make changes, how long until they're hoping to release it? A year yet?