Nexus S for T-Mobile gets brief Best Buy Mobile nod: there and gone again

Well, this was rather unexpected. Earlier today, Best Buy Mobile published a humble (if not incomplete) ad for the "Nexus S for T-Mobile," touting both its "pure Google" experience (i.e. vanilla Android) and holiday availability exclusively from Best Buy. It's gone now, saved only by the grace of Google cache. To be honest, all we can do is speculate beyond that. An anonymous tipster to RadioAndroid pegged the Nexus S name late last month and claimed it would feature Android 2.3 Gingerbread, a 4-inch Super AMOLED screen, and a Hummingbird processor. TechCrunch later described a Samsung-borne "Nexus Two" that has since been delayed due to some serious hardware issue. Is this a placeholder from the online devs? Does / did the S stand for Samsung, or something else entirely? And most importantly, is this presumed follow-up to Nexus One actually coming out, or did you just get your hopes up for nothing?