LazyGhost

OSS under what license? I don't see anything in a quick look over the repo.

Gruber does mention his rationale for not using a resolution that's close to this. Under "Other Resolutions" he says:

  1564 × 880 is feasible for a 5.5-inch phone.
  That’s what you get if you maintain the 326
  pixels-per-inch density and @2x scale. This
  would increase area — the number of points
  displayed on screen — by a whopping 89 percent.
  But it wouldn’t increase the size of what you
  see at all. I think the sweet spot for a
  5.5-inch phone requires you see to more content
  and to make what you see at least a little bit
  bigger. So that’s why I’d bet against 1564 × 880.
 (1564 × 880 would be implausible for the 4.7-inch
  phone: it would render UI elements and text 15
  percent smaller than all previous iPhones.)