I fondly remember a kit version of the ZX-80 that a group of us bought and built at the planetarium. I wrote software for it to reduce variable star observations we made with a photometer we'd bought for the observatory. The work of building it was really done by one of the planetarium associates, Ron, and he took the interesting approach of building it in something like an old portable case for some type of tape recorder I think. He also built a little keyboard with actual push buttons as an alternative to the little membrane keyboard the kit (and the ZX-80 computers) came with.