[jQuery] Autocomplete for hierarchical data (aka a "Tree")...

[jQuery] Autocomplete for hierarchical data (aka a "Tree")...


Before I go about re-inventing any wheels, I was wondering if anyone's see
any good Autocomplete plug-ins for handling hierarchical data organized in a
tree?
For those familiar with the program Quicken, I'm looking for something that
provides functionality similar to the "Category" field (which allows you to
start typing and then press the colon (":") to go to the children items.)
I have some text data that is hierarchical in nature. I looking to add some
kind of autocomplete functionality to an input element that will allow users
to select any of the end nodes.
Let's use this tree as an example:
Books, Music & Movies
    Books
    DVD
    Music
    Magazines & Newspapers
    VHS
    Video Games
    
Electronics
    Audio, TV & Home Theater
    Camera & Photo
    Cell Phones & Service
    Musical Instruments
Computer & Office
    All Business Center
    Computers & Add-Ons
    Office Products
    Software
When the user starts typing, they can only select from entries in the first
level (Books, Electronic, Computer.) Once the user types in some
delimiter--let's say a colon (:)--the user could then start typing and
choose from any of its children items. The user should be able to go as deep
in the tree as there is data.
I've been searching to see if anyone's already put together similar code,
but I haven't found anything.
Has anyone seen something similar in the wild? If not, it looks like I have
some work ahead of me. :)
-Dan