Okay, some crib notes about what I think I understand about adzerk/boot-test right now.
First off, they run some things inside of pod's in order to keep their dependencies isolated. This is the whole point of pods and why they're useful, but it's pretty slick how they're making that happen.
Secondly, my first impression that you must specify what ns's to test was flat out wrong. On reading the code it is clear that you can explicitly specify the namespaces to test, OR boot-test will just find all of the namespaces in your source dirs and search them for clojure namespaces using tools.namespace.
Finally, a lot of the code in boot-test is actually doing what the jUnit test runner will accomplish for me once I pass it a list of classes. This includes searching for the tests to run, then running them, then outputting intermediate results, then aggregating data about the results and finally throwing the results data if the tests had failures.
If I use what the jUnit console runner uses, I can get the output for free. So the main thing I need to do is implement the class finding analogues and then pull apart the java object into a useful clojure data structure of the results.