Kevin Broughan at Waikato Univ. (New Zealand) has built such
a system, not 100% though.   
There is also perhaps software that was written by Symbolics
but I don't know if it has been released in any other
forum.  The symbolics fortran compiler used arbitrary
precision integers;  Broughan's semantics for handling of
addresses in the middle of arrays (used in Fortran code
sometimes) was, at the time I saw it, not quite right.