OK, I have added support for including file attributes as properties to
org-fstree. You will need to use the merge_jtd_smiths_patch branch.
Once you have loaded org-fstree put the following in an orgfile and fill in the
directory name.
--8<---------------cut here---------------start------------->8---
* Disk usage
:PROPERTIES:
:COLUMNS: %80ITEM %size{+}
:END:
#+BEGIN: fstree :dir "<dir name>" :file-attributes (size)
#+END:
--8<---------------cut here---------------end--------------->8---
Hit C-c C-c on the #+BEGIN line to fill in the file details.