Autocomplete fields in Activeselect widget instead of dropdown and more

Would be nice to add combined ActiveSelect & Autocomplete widget.
It should be Activeselect like but using autocomplete fields on each or selected levels instead of dropdown selects. And allowing inserting new tags in a vocabulary with their parents.
In this case I see the Activeselect widget's config like:
First level bar: type - dropdown/autocomplete; new terms at this level - allow/deny
Second level bar: type - dropdown/autocomplete; new terms at this level - allow/deny
and so on (it would be nice to add more than 3 levels here)

Let me explain why we need it. We'd like to add a geography tag to our genealogical site for birthplaces/deathplaces and similar data.
We need depth detalisation e.g. Country->Region->District->City/Village.
1.Here first level of taxonomy is country and it is known(determinated) list. So first level settings would be type-dropdown (or autocomplete) and new terms denied
2.We know and have Region list for our primary country, but dunno for others. So second level setting would be autocoplete and allow new terms
and so on on next 2 levels.
This would allow site users to build geography taxonomy in process of adding their data.

And I think it will be great functionality for many other hierarchical taxonomies and will got "hierarchy" really to work.