I don't know of any formal case studies, but Adam Marcus and myself (two devs on the project) worked on a large-scale workflow at GoDaddy where we automatically organized data extraction experts into hierarchies of review. That work actually got published at a Databases conference: see Adam's nice summary here: http://blog.marcua.net/post/128120315677

On the research side of things, the flash teams work by Daniela Retelny at Stanford (http://stanfordhci.github.io/flash-teams/) has done great proof-of-concept things like build an app in a day with distributed teams.