this isn't what you are really asking for but i use 'folder marker'
http://www.foldermarker.com/ to do something similar. it isn't as quick as using a check box but being able to colour the folders does give you a quick way of referencing what you want to do. you can colour several folders at once - and, i suppose, one advantage is that you can create your own system to what the colours represent.
as an example this is what i'm currently using:
white folder = okay to delete
red folder = important
other colours denote the data inside them: light blue = images, black = downloads, etc, etc.
critical folders i've made that should never be deleted have an
! over them.
directory opus has the ability to use check boxes but it doesn't work in the tree. one thing directory opus does have are 'virtual' folders or 'collections'. this is what i use for collecting files/folders to copy to disk (or do something else to them).
a 'collection' can contain files/folders that are in separate places on the hard drive. so, the 'collection' behaves like a normal folder except that it's contents are not necessarily in one location. i find this very useful for preparing things to burn to cd - i have a 'burn to disc' collection. it's easy to send things to the collection - either through a right click 'send to' option or the usual drag/drop copy/paste methods.
when it's time to make the disc - i just open nero burning rom and drop the 'collections' contents into it. deleting the 'collection' doesn't delete the original data - unless you want it to - so, it's a very flexible way of working.
