It's actually fairly simple: I'm using the capybara selenium driver to run the JSpec tests and grab the results from the DOM when they finish. Here's the testcase:
I define an array of all my jspec tests, loop over them, munge them into a legal test method name and define a method that delegates to run_jspec. run_spec opens a file url (had to go underneath capy here so its a little icky) and then waits for the .failures div to appear. It should be noted that capybara will wait for an element to appear when you call page.has_css?
From here, running it under CI is trivial. In fact I didn't have to do anything at all, the tests was found by rake test:integrations and ran (and passed!) in the next build. Most of the heavy lifting is done by capybara and selenium-webdriver.
Obviously there is a lot that could be done to improve this code. I could grab the jspec file from a FileList, and grab some better failure messages from the DOM. I could also probably write a custom JSpec formatter to make this easier on myself even. I'm thinking if there is interest I could finish this up and turn it into a gem. Please comment if you'd use such a thing.
Also, one more thing you will need is the JSpec runner file that can run a single test. I did that like so: