This is very Tapestry-like (I've even borrowed the CSS styles). You can even see the start of the Request object's properties being displayed.
Something to notice here: Clojure stack frames are in Clojure syntax. To appreciate this, see what you get when you click the "Display hidden detail" button:
The exception report view is omitting a lot of clojure.lang internals, and it is working backwards from the mangled Java class name to the Clojure namespace and function name. This, plus only displaying the stack trace for the root exception, makes it much more reasonable to figure out where problems are actually occurring.
I expect to expand this further, adding a pop-up or hover window to display Clojure source associated with the stack frame.