Well, there is a MOS native version of BOCHS. It's a PC emulator, just not a terribly fast one.

So far, it can run some Linux, DOS and Windows. [However, you need to install the OS] On a Peg1 G3-600, it runs about the speed of a 17mHz Pentium. (Clocked by Rebel Assault II, DOS version).
There's also a MOS version of DOSBox, which is a dos emulator built to run old PC games (pre-EMS/XMS memory games.) It runs fairly well, and doesn't need an OS to be installed.
I tried to run PC Task on my MOS system, and umm, well, I can't get it to read a floppy on my Catweasel based floppy drive. I just get errors.
PCx won't even boot up.

I don't know about OS4, but I'm guessing that there will most likely be a port of BOCHS and DOSbox for it when soon after the OS is generally available. It's bound to work about the same.
Don't know if that helps?