Hey, I'm not too hip on the Japanese system, but I believe it is on ebay right now--seems to be brand new.
I am not positive this is the system that Family Stadium is played on, but if so, you Family Stadium fans might wanna take a look at this...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=38588&item=8111391803&rd=1
That auction is selling models or the original systems, not the console itself...
You can buy a converter on Ebay to play famicom games on a standard NES, that is the way to go for Family Stadium...