Sorry if this is too late (site went down just before I clicked to post the below):
Just Google'd it up for you and found that in this year's earlier promo, Delta changed the promo terms and conditions because initially they didn't exclude short-haul business elite flights. They quickly changed the terms (note, the language I'm quoting is for the analogous offer they had for Platinum status + 100k miles) to this language (bolding is mine):
If you meet the criteria to participate, you will receive Platinum Medallion status and Delta Sky Club® access for 60 days. The 60-day period will start upon enrollment in the promotion. In order to extend your Medallion status and Delta Sky Club membership after the 60 days, you’ll need to purchase and fly one qualifying BusinessElite® fare (fare classes J/C/D/I/Z) on a flight offering BusinessElite service within 60 days after enrolling. BusinessElite service is limited to the following long-haul international and transcontinental flights: (a) transatlantic, (b) transpacific, (c) transcontinental flights between John F. Kennedy/JFK and Los Angeles/LAX, San Francisco/SFO, and Seattle/SEA, and (d) between the U.S. and Brasilia/BSB, Buenos Aires/EZE, Lima/LIM, Rio de Janeiro/GIG, Santiago, Chile/SCL and Sao Paulo/GRU. Flights offering BusinessElite service may be modified by Delta at any time and without prior notice. Qualifying flight must be marketed and operated by Delta. Codeshare flights operated by carriers other than Delta are excluded from this offer. Only tickets purchased with a published fare that earns full mileage accrual will qualify. Upon taking a qualifying flight, your Medallion status will automatically be extended through February 2015, your Delta Sky Club membership will be extended an additional ten (10) months and you will earn 100,000 bonus miles. Bonus miles earned with this promotion do not count toward Medallion or Million Miler™ status.