The only thing that putting the emulator in the kernel buys you is
"exec", right? I've seen several good emulators which emulate the
original *environments* (Executor, for example: stunning mac emulator,
runs under nextstep, dos, linux [and thereby under netbsd via linux
emulation!]) that really wouldn't go well in a (non-swappable,
non-threaded!) kernel. 

Some sort of callout from exec to a server process (perhaps not
totally unlike the new linux "kerneld" mechanism) would seem to make
more sense...
			_Mark_ <eichin@kitten.gen.ma.us>
			The Herd of Kittens