Hello,
I am a second year MBA student at a highly-ranked public institution (not Harvard). Harvard is obviously a stronger brand than Mary Kay if Mary Kay is trying to use the Harvard brand to boost its own brand.

During the past year and a half of business school, I have probably read over 100 Harvard Business Cases. Read one today. The idea of a Mary Kay case study is pretty ridiculous. Cases are teaching tools. They give students a background on the company and then information regarding a serious issue the company faced. No solution to the issue is provided because discussing and researching the solution is how students' learn from cases. See this link for information from Harvard on how cases should be used: http://www.hbs.edu/mba/academics/howthecasemethodworks.html

In order for there to be a Mary Kay case study, Mary Kay would have to allowed Harvard to publish an article about a major issue the company faced without providing the company's solution to the issue (that is for the students to figure out and learn from). Students can't learn from half truths and Mary Kay probably wouldn't provide enough info to document a passable case study.

If you want to see what a REAL Harvard case looks like, you can download one for $6.95. Here is a link to purchase one I have studied for a class. http://hbr.org/product/henry-tam-and-the-mgi-team/an/404068-PDF-ENG?referral=00161

Happy reading!