Saavedra Turbo. Also sold as Wheelsmith Turbo. Long out of production and very possibly all used up and gone. Very low production item to start with. But still lighter than any clincher rim mentioned here. I built a 32 as a 16 spoke front, one cross, and did around 10k miles while weighing 185# before the brake track got too thin to trust. Front wheel was just over 500grams. Titanium spokes. Some kind of light hub, not nearly so light as what can be had now.
Price? The rim was free because no one trusted it. Felt fine to me downhill at 100kph.