Here is another thought:

What if Paarthunax were to claim he is an aspect of Kyne/Kyne reborn? Who would dare to stand up to him? Would the Graybeards say he is not?

And suddenly you have a reborn dragoncult.

Why would he say that, though? If something like this were to happen, I think it would be more likely that another "converted" dragon would kill/usurp Paarthurnax and make that claim. It may be wise not to trust a dovah, but Paarth has proved fairly trustworthy.

@Borommakot

I could not reply to your input so I had to reply to my own(Is it limited somehow?)

This is just speculation of course, but thats the fun part. So to speculate further, after getting off his mountain to convert the rest of the dragons to the way of the voice, then surrendering to his own nature of domination... Who would stand against him?

I would suggest that the Graybeards would have no choice but to believe. What would the dragonborn do? Maybe kill him afterall, and be known as the killer of Kyne for all eternity. 

(Yeah, the reply tree only goes down so far)

It's possible. I certainly wouldn't just dismiss the idea. But as the only dragon we know of to have any practice controlling himself, he seems the least likely to do something so drastic. If he did slip into his old ways, though, he would definitely be top dog.

Here is a question regarding the Dragon Priests. Vahlok the Jailor is abnormal because he's the only one without a mask, could it be that Konahrik is actually his mask and the reason he hasn't got it is because the Dragonborn traveled back in time with the Wooden Mask and took it?

Wow... I didnt even understand what I was reading...made my head spin.. What is the topic of this? PS. This is why I dont like TES lore (overall, mind). I have a feeling that they sort of just make up lore as they make game after game that stuff just overlaps... They dont have a dedicated lore group to work with the game-team (the people who make the actual game) so the stuff they say dont really add up when compared to the game.

The events of the Dragon War are only bits and pieces of remembered legend and myth. The writers do a fairly good job of remembering stuff but I don't think there is a dedicated lore team. In the case of Skyrim and the dragons, cult and war, it was all new lore written specifically for the game. If everything was seamless, there would be no room for the imagination like in Shaun's post above.

Thanks Ben  I corrected the typo too.

Agreed - this is one I need to read again.  Very, very interesting stuff!  I'm already thinking of how I could possibly incorporate it into a character...

It's all theory really, but I like trying to find new ways to look at things. I have been re-reading some of the very old forum posts from back when Skyrim lore was fresh. Kuhlmann's thoughts about Ysgramor and the possibility that "Ysgramor was not an individual but an amalgamation of several people - his reported exploits encompass an unreasonable amount of time for a single individual" offers another, perhaps more sensible, alternative to my Nord lifespan one. It raises other interesting questions about Ysgramor's lineage as well...

That said, my theory has the added bonus of sources that actually appear in-game