Dear Laurie,
This won't help with the "Microcosmic..." dance you were seeking, but David
Smukler has two triplets (one by him and one that he and Linda Leslie each
created independently of each other) containing contra corners on his website:
http://www.davidsmukler.syracusecountrydancers.org/DSS.html#corner_t
The old contra chestnut, Sackett's Harbor, a triple minor, also includes contra
corners. In that dance, the minor set of three couples has turned 90 degrees, so
it'smuch easier to identify corners than in a duple minor in long lines, where
the twos must be both first and second corners.
David Millstone
Lebanon, NH