RAAAAAAAAAAAAAAAAAAAAAAAAAAAINNNN!
Sorry, couldn't resist.
Sheesh i leave for 5 minutes and you've allready downgraded me to "lumbering barbarian"

As for the Red Dragon stuff. I too liked him in Ered where he spawned so lets just breakdown what you need and why. You wish to boarder in the clan to stop them becoming a super power? Personally i wanted the Clan to become strong i figured the end game heavy hitters to end up being the Clan and the Bannor supporter by their close like minded breathern.
But in the aims of facilitating you: lets see what we can do narrativly...
We could actually have Acheron being a muchh bigger player in this game by having him a founder and obvious semi-leader of the desert barbarian nation. We link Ered his current city to the middle then also place a boarder city to the west. (near to the clan where you desire it.) Then as gods we could move Acheron around his little Dragon worshiping empire as we please each intervention round. This would help me as i could easily link it into my own story line. It would also be helpful to the Gods as we would have more control over which city should be nigh unassailable for the round.
As Dragons are meant to be super intelligent it makes more sense for him to have a nation. The damn thing is huge. He would naturally find a place in a empire that worships dragons and wishes to become strong allways.
To link it in to the idea you had about the clan, he could indeed fly west to gain more money. Perhaps a Tithe as they used to say in medievil times?
Indeed the more i think about it the more i think it could work well while also allowing the dwarven quest to be finished sooner. However i am worries about how Lgaard was planning to link him into his quest. Were you in fact going to have Acheron as being the destroyer of the nation? that the horde was originally the dwarves? If so then yes we could merely have multiple hordes in the game one for the east and west (supplied by dwarf and orc), while the Death of Acheron could be the last part of the long term Dwarven quest (hitting around when Grigoria gets Dragon Slayers). This would be more fun for me as then Verdian would have to explore into the unknown desert to find the legendary barbarian nation founded by this great beast.
(Ideas? yes/no? currently i believe it is workable)
EDIT: Yes i got the pm. sorry i'm still new to figuring out all the parts of civforums so i missed it untill you mentioned it. I'll grab a drink and then figure out how to reply to the damn thing. Sounds interesting though.