per-app customization of request.dispatch has to be specified at a key of '/'
I'm not sure where the bug is, but I definitely tracked it to here - [source:trunk/cherrypy/_cprequest.py#L666]. Basic idea is that on line 674 trail == '/'. Which means the lookup into the app config won't work unless the request.dispatch was set in the path of [/].
See the soon to be attached script to demonstrate the issue. It has two options: failure and working. Run it with one or the other and browse to: * /things * /things/one * /things/two
Reported by lakin