That's why for apps like this (not for projects that I create with virtualenv) I much more prefer using OS package manager. Could it be any nicer than on Gentoo? ;]

  CDEPEND="dev-python/decorator
  	dev-python/pexpect
  	dev-python/pyparsing
  	dev-python/simplegeneric
  	virtual/python-argparse
  	emacs? ( app-emacs/python-mode virtual/emacs )
  	matplotlib? ( dev-python/matplotlib )
  	mongodb? ( dev-python/pymongo )
  	octave? ( dev-python/oct2py )
  	smp? ( dev-python/pyzmq )
  	wxwidgets? ( dev-python/wxpython )"
  RDEPEND="${CDEPEND}
  	notebook? ( >=www-servers/tornado-2.1
  			dev-python/pygments
  			dev-python/pyzmq )
  	qt4? ( || ( dev-python/PyQt4 dev-python/pyside )
  			dev-python/pygments
  			dev-python/pyzmq )"
  DEPEND="${CDEPEND}
  	test? ( dev-python/nose )"