For interested parties:
The three 4th Unit games released for Windows are on sale here.
http://www.suruga-ya.jp/search?category ... t&restrict[]=adult%20s(bool)=false
I'm not particularly interested, but someone else may be. These are quite rare, being the final games ever released by Data West (in 1999), and Acts 4 and 5 in particular were only available online to my knowledge. Of course AFAIK they are just re-releases of the same FM Towns games from 10 years earlier. And the other games in the series were never released on Windows.