While I wouldn't say that that we have a reusable framework, but we do have several principles that we follow. These are much like yours aaronpliu.
We always make sure that a test case is independently runnable on it's own, with no dependencies on other tests cases. This way we can always run an individual test case as required. We then group test cases into logical groups with test suites. This does mean we usually have a "Common Library" test suite, and then make extensive use to the Run TestCase Test Step to avoid duplication. I've spoke about this more here and here.
We also try to make use of Events to avoid duplication as well, I've detailed a couple of my event scripts here.
We run our tests via Jenkins on a nightly basis (personally I view the ReadyAPI GUI application like a development IDE), but also it's not always smooth, false failures just waste time and reduce confidence in the tests.
