When you search for case studies online, you'll often find that prominent business schools (such as Harvard, or UVA) will charge $6-$20 for a single case study. However, several library databases grant you access to authoritative and interesting case studies of all types:
VT's University Libraries has nearly 1,000 databases! In order to select the databases most relevant to your research topic, it can help to visit the Computer Science subject guide, which will point you in the right direction, in addition to highlighting basic reference texts related to CS.
I also recommend that you include the following databases in your search, after browsing the CS Subject Guide for some initial ideas: