A couple mint ones just came through Yahoo auctions.

Link is completed auctions for price reference.

Dana

https://auctions.yahoo.co.jp/closedsearch/closedsearch?p=mc28+%E3%83%95%E3%82%A7%E3%83%B3%E3%83%80%E3%83%BC&va=mc28+%E3%83%95%E3%82%A7%E3%83%B3%E3%83%80%E3%83%BC&b=1&n=100&select=2