Lightweight browser-based XML / Form editor for taxonomies withsupport f

[Lech Rzedzicki <xchaotic@gmail.com>]

Hi.

What would you recommend for authoring XML structures that look more
or less like this:

<root_element>
    <group xml:id="1">
        <name>A</name>
        <group xml:id="2">
            <name>B</name>
            <group xml:id="3">
                <name>C</name>
                <item xml:id="4">
                    <name>D</name>
                    <source></source>
                </item>
            </group>
        </group>
    </group>
</root_element>

Generally this is supposed to represent taxonomies in XML and the
deepest I have witnessed so far is 9 levels deep, but not necessarily
the limit, the taxonomies tend to get quite big as well, so I guess
it'd be good to only fetch a portion of the whole tree at a time...
XML seems like a perfect fit for representing such a taxonomy (is it?
- another discussion I guess) but I'm looking for an easy way to
prototype authoring of it - some button to add group or an item and
ideally a treeview UI element with a possibility of
collapsing/expanding portions of the tree.
So far I have looked at Axel and XForms but they don't seem to deal
with recursion that well (or do they)? Any suggestion are welcome -
perhaps a js library or a server-side framework - as long as it is sth
that will get me there with the least amount of plumbing...

Lech