Each sites' vhost has an Alias from /.dispatcher.php (which doesn't exist) to /var/www/cms/site/dispatcher.php. That's the only kind of link between the two. That main dispatcher handles everything via the classes that sit in the cms/class directory.

Use whatever method that makes you happy inside. For me a path like /foo/bar/blah?z=y would look like (in JSON):

{
  path: ['foo', 'bar', 'blah'],
  params: {z: 'y'}
}

A path like / just becomes:

{
  path: []
  params: {}
}

I don't treat it as a special case. If nothing implements the empty request, then a 404 would be triggered just as if someone went to '/asdfsadfasdfasdf'.

So you could create a Module_EmptyRequest if you wanted. It could just load index.tpl.

I always load Module_AutoTemplate as the last, catch-all module. It just looks for any matching template. So /foo/bar would match in order: /foo/bar/index.tpl, /foo/bar.tpl, /foo/index.tpl, /foo.tpl, /index.tpl.

The null case just naturally searches for /index.tpl.

Are you referring to requiring that function names match the URL? I don't like it. But there's nothing preventing taking my generic request handler function and farming out requests to individual methods.