A rather minor itch, which may or may not be worth implementing.
foo = importr("foo") looks slightly unpythonic to me. With the flexibility of Python's import system (e.g. https://github.com/njsmith/metamodule) it should be possible to provide a special package (e.g.
rpy2.rpackages) so that
from rpy2.rpackages import foo does "the right thing".