SuperModelers just celebrated its 1st anniversary not long ago, after started business on December 14th last year. I remembered that well, because it was during one of the events at the opening ceremony of SuperModelers that the audience voted Kshatriya over Sinanju as the next MG after Unicorn through a show of hands. See this previous posting.
The reason for the closing down was not being mentioned in the announcement, and it mentioned about a big announcement in the new year (新年には大きな発表をおこなう予定です。). Maybe the shop is shifting to a new location?
I believe it's better not to be too pessimistic about the news before further information is out ^^