@agramfort thanks for your patience -- this now open for discussion / review ;-)

And we directly hit into the first issue we did not consider.
Our clean Layout object now does not match with the old channel names in raw.
As a consequence, in this example no sensors significant are shown.

Options:
1) repeat the property trick from Layout in Raw, Epochs, Evoked, ICA and clean the channels on attribute access but not in info.

2) expose an explicit conversion function, e.g. make clean_names public,  in some examples.

Somehow I'm slightly minus 2 .... but 1 might introduce additional complexity.

cc @Eric89GXL @mluessi