why aren’t there daisy chainable USB drives out there?  for example; i buy two 4gb thumb drives, and i plug one into the back of another.  8gb drive in the eyes of the computer.  no complicated raid array setups, the drive controllers handle the file manipulation for you so you have 8gb of space.  you could plug either one into a computer and see all the files on it without any setup.

seems like a damn good idea to me.