Seattube length means nothing. Standover is all that matters in that area. Unless you're under 5'5" That's perfect. I agree the 6.6 SS is what you need. Just make sure you run a though-axle if it used 10mm drops. QRs on 6.6s are crazy flexy. You can move the side be side inches by hand. The regular 6.6 definitely requires a though axle. I'm not sur what the drop-ou options are on the SS both jus make sure it's a through.^That looks sick! My only worry is the 17" seat tube.
Dude have you looked at the canfield balance? What about the Corsair Marque with a headangle that can be set as 66 degrees. A 160mm All-mountain bike with a 66 degree ha sound like what you want.