It's not I want to dismiss but until I see proof I don't believe what people tells me.
We discussed two things, 1)The X1000 similarity to the Devcon93 papers, and the 3.x Sourcecode actually used in OS4.
1) I told that the X1000 is very similar to what was described at devcon93 (generic mobo with modular components) and I explained to you why I reached that conlcusion: the last amiga they talked about (hombre was no Amiga) at 1993 devcon was to have the AAA chip-set as a modular interchangeable board, the whole project was ditched, we know that, but if for a moment we want to forecast what would have happened in case they made it, we can clearly see that by 1996/97 off the shelf GPUs, which were advancing at the pace of a new chip every 3 months at the time (from 10 different companies) would have replaced any chip-set C= had in mind (with the difference that in the A4000 adding an RTG card still leaves the old chipset there, with that new Amiga, after taking AAA away, there would be no GFX chipset left inside the machine) and by today any Amiga would use Ati or Nvidia GPUs (there was no competing with that evolution speed, too fast).
You told me that, "that could be said of any modern PC" but it would seem that you fail to realize that that's how the world went.
GFX chipsets in this survival of the fittest rolling ball we live in, lost their battle and went extinct regardless of Amiga, so saying the X1000 is no Amiga because of lack of fabled chip sets is absurd.
2) source code: I only see talks about the NG exec there ( and warp3D and elf), the C parts I talked about were in Intuition, and other components, they commented on several occasions the C part is used at least as a base for many things (now OS4.1Up2 has a lot of updated components so who knows).
I believe them and don't see any evidence in the documents you posted, moreover if we don't check the actual sources, we'll never know for sure (is their words against yours).
Notice that it is you who is trying to be authoritative, I only post my impressions and explain "why" I have them.