Actually, i think you're right on track in your way of thinking .... I usually find sds and myself in agreement, but I think Australia.Is is a branding/marketing wet dream. From a "pure domaining" standpoint you have very little value, but looking at it as "Australia Is ..." just seems like the start of a massive marketing campaign.
I don't know what you could get for it in the domaining market (probably not much),but whatever anybody is likely to offer you, multiply it times 10-20 and take it to the marketing/travel industry rather than domainers.
Frank
