Reported on the Japanese site Akiba PC Hotline. A new Memory Expansion I/O Kit is being sold for the Sharp X68000 series of Japanese computers. Designed to interface with any model X68000, this memory unit can be setup and configured via DIP switches to various memory setups including 2MB, 4MB, 6MB, 8MB, and 10MB. Coupling this with the on board memory. A total of 12MB can be achieved for the computers maximum capacity. The store called BEEP in the Akihabara district in Tokyo, Japan is selling these units.
Links: Japanese News Site – https://akiba-pc.watch.impress.co.jp/docs/news/news/1205/667/index.html?__twitter_impression=true
Store Front – https://akiba-pc.watch.impress.co.jp/shop/at/beep.html