Ron Jacobs compiled a great series of five ARCast episodes with a company doing a SaaS (Software as a Service) application. Have a look!

ARCast.TV - SaaS @ Work - Remend Overview
ARCast.TV - SaaS @ Work - Remend Architecture Overview
ARCast.TV - SaaS @ Work - Remend Architecture Drilldown on Workflow and Services
ARCast.TV - SaaS @ Work - Remend User Experience
ARCast TV - SaaS @ Work - Remend Database Architecture