This site, which was born from Stanford, provides a single database to documents all patent litigation:

In order to study disparities and other trends in patent litigation, some of the world’s biggest technology companies and law firms funded a team of IP experts and leading computer scientists to map out every electronically available patent litigation event and outcome. The result of this collaboration was the IP Litigation Clearinghouse (IPLC), the most legally rigorous patent litigation database and search engine in the world. The IPLC was launched in December 2008 as a fully searchable web-based “almanac” on U.S. IP litigation.

Update: This report discusses their research.

To ensure comprehensiveness, we identified relevant cases in two independent ways. The first, employing attorneys and artificial intelligence experts on the IPLC database, swept over 31,000 U.S. patent infringement lawsuits and 1.7 million contemporaneous litigation events. See Ex. A. The second legal team searched using exogenous, state of the art methodologies and tools. Then the two preliminary result sets were combined and analyzed.

Lex Machina verified 90 (ninety) federal cases or case clusters (i.e., groups of related lawsuits) with one or more “merits analysis event” on § 102(g)(2). Id. A prototypical merits analysis event (or “MAE”) is a summary judgment order, but it may also be a Federal Circuit opinion, a trial outcome, a substantive evidentiary order, or another judicial analysis.

This discusses their features.

The IP clearinghouse is discussed on SSRN here. And here is how they got their data:

The data set is derived from PACER (Public Access to Court Electronic Records), an electronic service that allows users to obtain case and docket information from federal courts. After downloading all available cases from more than ninety courts (and by hand-collecting and scanning documents from others), raw data sets are parsed by a computer program into specific motions, objections, and decisions. The data is then hand-checked by research assistants to ensure integrity. Associated documents also are made available.

From The Economist, TechCrunch (It’s expensive–“Lex Machina is announcing free access to its service for small mobile app makers who have been sued (not a bad deal considering access is usually $10,000 per year, per seat on the SaaS model).”),