A user on Reddit pointed out this Twitch stream that shows the BlazBlue Cross Tag Battle Collector's Edition Switch steel case alongside the PS4 steel case. It doesn't look to be a Steelbook to me, but I'm still kind of new to this and may be wrong. Source:
https://www.twitch.tv/videos/249332244 The cases are shown at 1:01:45.
Arc System Works also responded to my email and this is what they had to say about the American BBTag CE: "The Switch version of steel case is the size of the Switch game package. It is slightly bigger than the normal case due to the material, but it is almost the same size!"
I'm going to move both releases to the confirmed size category, and will be able to give a better update once I receive both my Asia and American releases.