You can expand the List view to look like your description. You can select files within each subfolder. Multi-select by holding down the Command key.
Tagging solves the ultimate problem--inflexible organizational decisions--not the one you are asking about.
If you tag the files with, "Client", "Bird,"Color," "BW," etc
Those tags may be specific, like "Bob" and "Sparrow" or left generic like color and BW. You could also use a combination, such as "Clients" (general) and "Bob" (specific).
For example, your file 002 inside the BW folder could be tagged with, "Clients", "Bob", "BW", "Birds", and "Sparrow"
Instead of moving the file, you can delete the BW tag and replace it with another more appropriate tag.
Using spotlight, you can then search for any combination of your tags to get to the files you want.
You are "virtually" filing your images by Tag instead of by folder.
You could store the files in a folder structure that is not so complex, or no complexity at all.
If these are all just image files, then using a dedicated storage system such as iPhoto or Aperture would be better and provide similar Tagging with Keywords.