It's quite likely that you've never heard of the following Apple II+ clone. Why? The thing wasn't very successful, as it was announced back in 1984, but wasn't released on the market until 1986.

The special thing about the Spartan was, that it was a kind of add-on module for the Commodore 64, and made it compatible with the Apple II+. Sounds a bit strange? It is, because in the box was almost a complete Apple II+ but in a different housing. Only keyboard and monitor were shared by both devices.

Nevertheless, an interesting idea researched and written up by David L. Farquhar. The hardware can be found from "rarely“ over "very rarely“ to "never" on the relevant platforms. Therefore rather something for collectors than for hobbyists. 

But if you still have this box somewhere in your basement or attic, and don't know what exactly this thing is, then the article will surely make you a little smarter. And Ebay might make you a few colorful bills richer. 💵