My suggestion, however, is not nullified. No Great Dragon would have any significant leverage over any other; the Great Dragon Corporation (GDC) would be, for all intents and purposes, a front. A very sizeable, very significant front company, I agree, but a front company nonetheless. Consider the history of the Zurich-Orbital Gemeinschaft Bank.
Seven corporations, heavily in debt to the most significant world lender, get together and perform a buyout upon the bank. The bank winds up having so much capital and influence via its shareholding corporations, it can functionally declare new nations (in the form of multinational AA-rated corporations) the world over, nations which other, actual nations, are required to recognize - and recognize the extraterritoriality of. In this way, those Big 7 essentially made the leap from 'really big fraggin' company' to 'independent corporate nation-state'. They may now be the Big 10, but they still a) possess strictly equal shares in the corporation that gives them authority (i.e. ZOG), and b) are still generally at odds with each other. Consider the chances of Saeder-Krupp cooperating with Aztechnology ...
... then realize that at a certain level, in very restricted ways, they do so on a day-to-day basis.
That's the sort of thing I think the Great Dragons might realize they need to do in order to survive and thrive in the modern world. Oh, great dragons are incredibly powerful, and most if not all of them have amazing amounts of corporate holdings and influence, but in the larger scheme of things, that does not eliminate their functional vulnerability to what Sirrurg faces - a direct challenge to a right they've had all their lives, of being apart and above metahuman laws. In the Second Age, the dragons ruled completely, incontestably. In the Fourth Age, the dragons no longer ruled, but could act with relative impunity, and answered to no law but their own. Now, in the Sixth Age, humanity's rapid development of technology and increasing knowledge of magic means that even at this early stage, in less than half a decade (incredibly swiftly in the eyes of a GD) an act which would have gone unanswered in the 4th Age has earned a Great Dragon injuries, perhaps serious ones. The ephemerals have got very real and very dangerous teeth.
Doing this isn't the only way, I'm sure, for Great Dragon society to establish itself as a seperate entity, beholden primarily to their own laws, but it is the swiftest, most sure way to use metahuman laws against metahumanity in the establishment of the rights and untouchability of the Great Dragons. Like the megacorporations, they don't have to agree to most things - only to this one little sub-section of things.
But if they manage it, watch out ...