In the documentation for the Axis object, I see that there is supposed to be a transAxis attribute. However, when grepping for it in the source, the only place it appears is in the documentation:
grout@...757...:~/sage/local/lib/python2.6/site-packages/matplotlib$ grep -r transAxis *
axis.py: * :attr:`transAxis` - transform axis coords to display coords
Binary file axis.pyc matches
Has this attribute been removed? This is with version 0.99.0.