my suggestion would be provide a whl_setup.py that works in a fashion
similar to the current ez_setup
however instead of using easy_install + eggs, it would use pip install
--target into a folder relative to the setup.py that invoked it
if there was a mechanism to prevent pip from invoking
Take this setup.py that implements setup requirements (requirements needed
for setup.py itself to run)
https://bitbucket.org/dholth/setup-requires/src/tip/setup.py
Require your new build system using that mechanism, by mentioning it in
setup.cfg
Then instead of calling setup() from setuptools at
