@Methusales
It seems you really got something wrong here ....
I assume that by "on the fly" you mean the JIT-compiler,
wich says nothing if it is either a boxed system or not.
It also doesn't matter if you run one 68k-emu, or one per task.
The only difference between "boxed" or "not boxed" is wether
the old SW is kept seperated from the new one, or if it all runs
on one kernel.
Very importont to what kind of memory-protection and so could be
implemented into the OS.
Oh and yes it seems that the orginal poster really didn't know
if OS4 was 68k or PPC.