D, the problem is they are head-strong on the licensing issue. They don't want to sell AOS4. They want to sell dongled computers, not Apple Macs.
As we're on this topic it ought to be possible to port Darwin/PPC to the Pegasos or Pegasos II. Although by the time that happens you may be able to get a used Mac for less.
It would also be possible, although difficult, to execute Darwin binaries on Quark much like you can run Linux/x86 binaries on NetBSD. IOKit (or some parts of it) would have to be ported to Quark.