> by encoding groups of symbols instead of the symbols themselves you
> can achieve a much better compression rate.  This could translate
> into interpreting groups of bytecodes at a time instead of the
> bytecodes directly, but then only the interpreter needs to change,
> not necessarily the bytecode set.

Exactly.  <http://www-sor.inria.fr/publi/ODCSI_pldi98.html> explains
how to do it.

Ian