App/Dev Dept, Organizational Structure?

We are currently looking at restructuring our App/dev department as we “centralize” our organization from a number of small groups of dev/DBA staff working within user departments, supporting their local applications to a organizational pool of App/Dev resources that are assigned to projects as required. (If that makes sense at all!!)

We are looking to restructure into the following units;
Business Analysis/Project Management
Application Development
Application Maintenance

With this brief description does anyone work in a similar environment, or an app/dev structure that works really well that could possibly be adapted here? Any direction/opinion is appreciated.

Thanks
Jim