The Case Centre (formerly ECCH)
It has studies from a number of different universities, including Harvard, Stanford, Babson, Darden, etc. From their website: Over 24,000 cases on all aspects of national and international business and management, authored worldwide, are available in the ecch case collection. Most cases are in English, with about 250 cases also available in another language. A typical case may average between ten and thirty slides with some supporting graphics or data. Purchase information is included on their website.