Hmm, are you saying about translating from one language to another, or
you speaking about translating VM code?
The only things, which can improve performance is to translate code to
bare metal (as Exupery does). Translation to another language (or to
another VM) is much less effective.
Don't forget, that any VM/compiler is designed to be optimal for a
target language, so even if you try as hard as you can, you can't run
smalltalk with high speeds if your VM is not specialized to run
smalltalk.

-- 
Best regards,
Igor Stasenko AKA sig.