The Original MS-DOS 4.0

This might be a topic better posted in the alt.folklore.computers USENET group, but let me try here first. This is from memory, and it's not as reliable as I'd like it to be. IIRC, OS/2 was not Microsoft's first attempt to create a multitasking operating system. They were working on, and I believe mostly finished, a DOS 4.0 that was multitasking. This was not the PC-DOS 4.0 for IBM, nor was it the MS-DOS 4.0 that we finally saw here in the states. This multitasking DOS 4.0 (from Microsoft, not a third party) was supplied with a computer that was old only in either the UK or more widely in Europe. It seems that the first letter of the computer manufacturer was an 'A', so the machine could have been an Apricot, an Amstrad, an Acorn, or lord knows. I read about this machine either in Byte during the late 80s or in a BIX conference (I MISS BIX!). I've searched the web for references to this multitasking MS-DOS 4, and have found nothing. Does anyone else remember this? Was the Byte article reviewing a sample of a product that never shipped? Did anyone get their hands on one? Does anyone have it? -doug q