Is there any font encoding the second stage of simplification? Of course, it should not even be mapped to their original Unicode positions, they could be sent to Private Use Area planes, but is there any way to typeset the extra-simplified characters as delineated, say, in http://std.dkuug.dk/jtc1/sc2/wg2/docs/n3695.pdf?
I understand from the author of that proposal that these characters will be in Unicode when CJK Extension G is adopted sometime next year.  In the meantime, they are available in his font Babelstone Han PUA.