How to reconfigure dynamically the parameters that aren't latched to particular nodes?

`Parameters` can be declared w/o being associated with any node ([ref](http://answers.ros.org/question/11914/how-to-declare-common-parameter/)). Looks like [dynamic_reconfigure](http://www.ros.org/wiki/dynamic_reconfigure) targets only those params that are associated with **nodes** (indeed I'm seeing on its GUI `reconfigure_gui` that the params w/o nodes are NOT shown. (eg. /base_controller/* on PR2)). If I want to update those "independent" params as `dynamic_reconfigure` does to the dependent params, is there a way provided by ROS or what would be the best way to do so? ps. I prefer to using `rospy` for implementing my stuff. ---- Edit) pps. I don't have to stick to `dynamic_reconfigure` for this purpose, although using it for handling node-related-params is my first option. ---- Edit-2) The features of `dynamic_reconfigure` @joq listed are not only nice but also sound critical, in addition to the fact that `Parameter Server` API isn't thread-safe. After hearing about `getParamCached()`, I now think about making a C++ node that gets & updates parameters and publish them as `topic` or else. But I'm still curious to hear another opinion.