There seems to be no way to skip the build step when running "setup.py
install" The behavior in such a case should be to skip build and use the
existing binaries as created in a separate build step or else print an
error. That way you can do "setup.py build" followed by "setup.py
install --skip-build" and you only have one build taking place.

The purpose of this would be to allow build to take place on a separate
computer to install. Currently I do this on Vista because MSVC 2003 is
not recommended or supported, and distutils won't use the installed MSVC
2005. So I do the build on a (virtual) XP machine and then install by
hand for lack of this option. I think Vista is a strong enough use case
to justify adding this feature.