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 !
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.