Just to be clear, supporting Hierachical URLs is something we want to do.
It's purely a case of it being a complex task that requires either
a) a kind and progressive commercial client to fund it for open source release,
b) donations so that we can pay our core developers to do it
c) or a competent PHP5/SilverStripe programmer to donate time to work with the core development team.
In my work on silverstripe.com I find myself wishing for the feature, and I would state the first goal is to allow URLs the below to be unique and logically representing their position within a sitemap.
So, taking the previous example...
The idea is to allow the two 'staff' pages to not default to "staff" and "staff-2", but to contain "office" and "stockholm/gothenburg" in the URLs.
Whether the deliminator is a hyphen or a slash depends on the level of time/money we get, with slashes being seen is the ideal, but more difficult, goal.
If someone was keen to help out let us now ... I'm firstname.lastname@example.org