Ski needs a custom guest kernel however, so I had to cross-compile that for ia64.
When compiling the toolchain yourself, note that you may need more/other library packages then listed in the HOWTO. This depends on the target architecture, e.g. for ia64 you will need libunwind7-dev, libatomic-ops-dev, and further libc6.1 instead of libc6. Otherwise gcc will complain about missing build-dependencies.
While doing all this I wrote some scripts to automate the process, so
compiling a cross-toolchain (for any architecture) is now a matter of 5 minutes
configuration and one
./driver run. Whee!