I've been coding more of Cascadeand I'm tending to do lots of small namespaces. I'm concerned about circular dependencies, so I've been using OmniGraffle to keep track of what uses what:
I end up keeping this open in the background and updating it manually as I add new namespaces or change dependencies. I'm pretty sure it's accurate.
This seems like something I should automate at some point, however: It should be possible to use the reader to parse a Clojure source file without evaluating it; the first form should be the (ns), from which can be expanded the used and required namespaces (with a bit of effort, because of Clojure's very concise syntax). One more project for the back burner