Have a look at this demo: cascadingcombobox.html
That is the way that our (wikidot's) pagepath works… only they made a better interface… but we (Wikidot) have the extra ability to add a new item…
WHAT WOULD HAPPEN IF THOSE WORLDS WOULD COLLIDE !?
Heaven on wikidot-earth?
This is kind of the same wish as hoping for all values to be visible in a pagepath-select like in breadcrumbs
And beeing able to limit the depth of the pagepath… formulated in an other wish.
So it would be nice if this would become reality… but those other wishes are more urgent.