Cannondale Prophet is about 66deg in the slack setting and climbs great. Total blast on the way down too. You just have to budget for replacement pivot bearings every couple of months. The Lapierre Zesty is also abut 66.5 and climbs fine (the longer chain stays keep you from tipping over the back and make it super stable at speed, would make a killer a Megavalanche bike) as was last year's Meta 5.5.

Slacker than average head angled aren't inherently bad at climbing or twisty singletrack. Therre's more to it than that. The Pitch for instance climbs ok for a heavyish bike because it has a steep effective seat angle which keeps your weight over the fron end.

I think most world cup DH bike are about 64/64.5 nowadays. The manufacturers may not admit that, but that's what people are riding.