VM/386 was a multi-tasking multi-user product for 386 based computers. It was put out by the seemingly now defunct IGC corporation. VM/386 is a multi-tasking operating system that takes advantage of the vm86 feature of the 80386 and higher processors.
Like Novell Netware, it is launched from within MS-DOS, but after that it runs in protected mode. IGC was part of the committee that designed DPMI so I'd assume later versions of the product can run DPMI executables.
I've got versions 1.2 and 1.22 and neither run under any kind of emulation so I haven't been able to do much testing.