I'm going to guess they wont unless a US carrier picks up the 950 XL. The only reason they are selling the 950 is because AT&T is offering it. They typically go with carrier offerings as there's greater margin on selling the upgrades and lines of service than the devices themselves.
I would assume they may eventually sell it as badmojo69 mentioned. They do sell Microsoft products within their store. We may carry it a few months later. The only reason we got the 950 in is probably cause ATT offers it, but at the store in Louisiana we only received one. It may just depend on how well the 950's sell.
I would imagine sometime in the next couple of months only cause stock is hard to find at the moment.