Is there some package that manages various tree structure?

[Young Ju Song <stankonlines@gmail.com>]

Hello!
I'm a newbie Emacs user who migrated from vim about 4 months ago.
This is first time for me to mail here and I'm not sure if this is right
place for my question...

Inside Emacs, I work with various tree structures, such as
- undo-tree
- directory structure (direx, neo-tree, etc. nerdtree in vim)
- org mode (I haven't seen tree visualization of org document, but it
basically can be seen as a tree structure with each headline as a node)

Also, I think following can be presented as a tree inside Emacs even though
I haven't seen yet
- proof tree (http://askra.de/software/prooftree/)
- buffer. I really love Firefox's tree-style tab plugin and I think similar
idea can be applied to Emacs. (can be well defined as follows : if buffer A
is opened inside buffer B, A is children of B) I usually open various
buffers including Coq&ProofGeneral things, Octopress blogging things,
sshing to machine and C/C++ programming things, etc which can be well
organized with tree structure.
- git commits. If we impose edge to both parents in merge operation, this
can be seen as a tree.

I think it would be great to have some layer which grants unity while
representing/manipulating tree structure.
Representing (data level) may include original data, contracted data
(minimal graph homeomorphic to original graph, smoothing out all vertices
with degree 2. It may be useful for undo-tree), etc.
Representing (visual level) may include nerdtree style, (growing
horizontal)  undo-tree style, (growing vertical), etc.
Manipulating may include moving cursor from node to node(to parent, to
child, to sibling), visiting current node,
(&optional) moving a node, moving a node and its children recursively, etc.
I found this package (https://github.com/kiwanami/emacs-ctable) which looks
like having similar idea with me except that this is for table.
If there is something like what I have described, please let me know.
If there is not, does it sound realistic to make one?
Any comments or advices are welcome!
Thanks for reading.

Frederick Song