runtest.py was really only meant to be a simple run script when you're getting started. It's really meant more as a convenience for running locally as you're developing the test. As you need to do more advanced things like reporting, handling test tags, and publishing artifacts, you'll want to create your own build scripts custom build scripts to fit your business needs. Back when I was with Wiredrive, we had shovel scripts that ran nose directly, passing it custom parameters and using different nose plugins .
https://github.com/seomoz/shovel
For targeted test running, we used a tagging system to tag test cases with the features and components the tests tested. We used a shovel task that created nosetest parameters like '-a testtype_smoketests,feature_authentication', and appended it into a command and executed it.