@ APair
You will really struggle to find a case in good condition, on its own. It's bad enough trying to get a good condition A4000T (complete).
I looked for a long time, for a new case because mine is in scruffy condition. Some guys will sell, but there is a problem, usually it involves a missing or damaged bezel. For example TomSwift was selling a case a while ago, but it had no door.
The cases used on A4000Ts (Amiga Technologies) are Enlight cases. Check my pictures for more info, and check my thread on A4000T.