I am aware that Requests\Sec, Requests Total etc. counters are available for free (they just need to be set up to be collected and transferred). Is anyone aware of any counters that are available which give some data based split by the http request url? So requests/sec for a specific url on the service? Just want to make sure there isn't anything before I head off writing custom per counters.
You will need to write your own. I've helped do this for a customer who uses MVC framework. It was super easy, as the only code needed to be instrumented was in the OnActionExecuting method for needed controllers.
Do make sure to instrument the creation of a custom performance counter definition via a startup script like described here (step #2): http://www.windowsazure.com/en-us/develop/net/common-tasks/performance-profiling/