Wow, it's not often that I read about a site that is this daunting.
If you've already sacrificed two weather stations to Poseidon what do you think he's going to do with a wind turbine?
Whatever turbine you choose, it will probably need some modifications to harden it against a number of factors:
1) Wind gradient from the top-going tip to the bottom-going tip will cause a significant 1/rev vibration,
2) Vertical wind currents racing over the ridge will also cause a 1/rev vibration,
3) Winds following the ridge may develop eddies if there is rough terrain causing a 3/rev vibration for a 3-bladed turbine,
4) Limited guy bracing options due to the ridge.
On the other hand, the promise of strong consistent wind is undeniable. The height of the ridge will increase the general wind speed at the turbine hub, too. If you contact wind turbine builders and show them this wind rose, they may be enticed by the challenge. Remember Proven? They kept the picture of their machine in Antarctica on their website for years. It would be a good "shakedown" trial for anyone's machine to survive your environment.
I would insist on a tower that is over-designed, and rather stubby - the penalty in tower height is made up for by the ridge height. I don't think your site really needs towers. By keeping the tower height low, you also give yourself a better chance of making a proper 4-point guy wire " + " pattern. Consider maybe an " X " pattern so that there aren't 2 wires going straight down the slope of the ridge.
When storms come, you don't want to mess with the tower, but you will survive if the WT is equipped TWO of the following:
1) electric dynamic brake
2) mechanical/hydraulic brake
3) blade pitch to feather
I don't think just one of these is enough. What if one fails?
I doubt that a WT that relies on tail furling will survive in this environment. The size you want is already on the big side for tail furling and the conditions make it crazy. Furling is a dynamic thing that puts a gyroscopic moment on the top of your tower and the bearings it yaws around. The stronger the wind the stronger the torque and you have some very strong wings. Besides, what would be the point of installing a WT that's furled 20% of the time because the wind is too high!? I've never even considered this question before.
I have been impressed by the sturdiness of my motor-conversion machine with its 2.5 meter blades but the stormy winds here rarely past 100 klicks. I would dearly love to build a big brother and fly it in winds like yours, just for the sake of the challenge. But any company that doesn't want to lose their shirt in warranty replacement costs will respond to you very carefully.
If you are looking at american companies, Bergey is probably your first best place to start. Phone them up and get talking - this might not be an off-the-shelf purchase; I have heard that they still listen to their customers. They have so many machines installed around the world this is probably a problem they've already solved. Their Excel has a furling tail so I'm not sure this is right for you.
I'm really looking forward to what you can find and how it will work!