Hi,
I have been adding some information regarding components and patterns to http://www.mediawiki.org/wiki/Wikimedia_Foundation_Design/Patterns_and_compo...
The content is very raw at the moment, since it is based on the patterns and components I have been applying in the projects I have been involved these months (Universal Language selector and Article Feedback). The idea is to allow anybody to refine, correct, add examples, and discuss the proposed recommendations where they think the solution proposed is not the best for a specific context. In this way we can go from the specific to the general (promoting our particular project solutions into general recommendations) and the other way around (applying improvements to the general patterns to the projects they are using them).
I'll keep adding more information.
Pau