UK-NC -- school computer (was not available in stores). Two CPUs (second CPU used for I/O, sound etc.) with PDP-11 instruction set, color graphics, sound, integrated keyboard, serial networking. Teacher's workstation also had dual 5" floppy drives, printer, and (sometimes) color monitor; several RT-11-derived operating systems were available, and lots of commercial educational software.
Hackers over at zx.pk.ru [1] have found a hidden/poorly documented color mode (8 fixed palettes of 8 colors at low and high intensity, selectable for individual scan lines) and there's talk of porting/writing games for this hardware :-)
[1]
http://zx.pk.ru/showpost.php?p=570148&postcount=80Mock-up screenshots: