On one of the Theory of Constraints mailing lists, someone pointed to the work of Nelson Repenning and John Sterman, who both focus on various aspects of process improvement. Specifically, there are a couple interesting case studies attached to an abstract for Capability Traps and Self-Confirming Attribution Errors in the Dynamics of Process Improvement. The article title is a mouthful and is only available from the journal in which it was published, but the axillary case studies offer an interesting view of process improvement efforts in manufacturing and product development.
The first case study (pdf) is a manufacturing environment which had an overall focus on Manufacturing Cycle Time (MCT) reduction. The case goes through the history of the improvements at two plants of a large manufacturer. The improvements discussed do not start with TOC but with other improvement efforts - all geared around getting cycle time down from about a week down to one day. But it is TOC that is claimed to provide the biggest benefit toward getting the groups down to that one-day goal and in helping the shop-floor employees become part of the process. The case also talks about where TOC and Drum-Buffer-Rope had to be modified to fit the scenario.
The second case study (pdf) focuses on the product development process (PDP) in the same company - again focused on reducing the cycle time of the process. The general description of the process should sound familiar to people who have looked at stage gate processes in new product development. Rather than TOC, there are more elements in here for knowledge management and project management within this case. In the late 1980's and early 1990's they were trying to solve the problem of knowledge sharing and learning lessons from one project to another.