I came across http://www.muscula.com/ over the weekend, and they seem to be farther along with this kind of a product in terms of features (not to discourage you, just to give you a heads up as to what else is out there). Specifically, they've implemented a stack trace and also provide the browser/OS data in addition to the file/line/error.
They also provide a quick overview of their architecture if anyone is curious @ http://www.muscula.com/architecture