If you use Trac http://trac.edgewall.org/ you may be interested in a
plugin I wrote that helps orchestrate chef nodes in AWS:
The plugin can be viewed as a UI and coordination wrapper to
boto http://code.google.com/p/boto/ (python-based AWS API). I’ve been
using it for four months now in production and it has enabled us to get to
push-button deployments (including serial to clustered nodes behind a load
balancer) amongst other management benefits.
I recognize there’s been some chatter on chef-based orchestration so I look
forward to seeing how these efforts can evolve together.