As it stands, the gcc-multilib (and g++-multilib) package provides a number of cross-compilers for the architectures debian supports. i.e. gcc-hppa64-linux-gnu (the same for gfortran, gdc, and so on).
Is there any particular reason it does not provide cross-compilers for the different kernels debian supports? i.e gcc-i686-hurd-gnu or whatever the triplet is