Thanks for the update.
My work ordered a Dell 5510 for me, so I've put my personal machine upgrade plans on hold. I'm still hoping Dell and/or Lenovo will upgrade some of the i7-6820HQ systems to i7-6870HQ (and no dGPU) once the latter is actually available.
The latter should be soon; the first system using the quad-core-Skylake Iris Pro CPUs -- the Intel Skull Canyon NUC -- has finally gone up for pre-order today.. Whether/if that turns into orderable laptop systems with those CPUs from anyone else is an open question.