Gdome and External node data?

Hello, I'm new to the list.  I am thinking about using gdome as a
framework for DOM access to my XML trees.  Most of the stuff I do
involves creating custom XML trees to allow for extra data attached to
nodes.  I was wondering if Gdome allows for either arbitrary data to be
attached to nodes or the ability to subclass Gdome nodes to include new
functionality while still being able to "look" like a Gdome tree to the
Gdome interfaces? To clear things up I will give an example of what I
would like to do.

Take SVG for example.  SVG objects should be able to be manipulated
through standard DOM interfaces.  The problem here is that the majority
of SVG attributes are manipulated as floats and integers, on top of that
SVG provides shortcuts by allowing grouping what would usualy be done by
multiple tags or attributes into one attribute.  To access the simple
attributes as text would be both slow and require parsing of the
attributes every time a point needed to be changed.  What I want to do
is develop a sort of standard style sheet for each node that would be
updated when attributes are changed in Gdome or which could be directly
manipulated by programs that understood the extra data in each node. 
This would allow for standard access from scripts (i.e. I know the line
node with have a list of x,y's of type integer no matter what format the
tag was in)  and allow for quick manipulation from internal C
functionality for perhaps drawing the SVG graphics to the screen or
other such functionality that depends on speed.

My other question is can Gdome's scripting bindings be passed a Gdome
tree from C, manipulate it and return the results back?  In otherwords
can I use multiple languages to modify the same tree?  It would be great
to allow any scripting language supported by Gdome to be attach to event
handlers such as onMouseOver="perl:doRollover".

Thanks

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J5