Well, I have...
Figure 1.0: Taking Something Horrible and Making It Worse
Don't worry - At the moment this is nothing more than a stupid picture and a hunk of protoboard jammed into the top of an unsuspecting Arduino. Implementing a floppy drive controller in software would be a bit of a challenge, however there is no reason it couldn't be done; though some(most) would argue it shouldn't.
For some reason floppy drives make me smile whenever I see them. I'm not sure whether it's their uselessly small data storage capacity or that satisfying "ka-chunck" sound when loading a diskette into a drive, but there's something there that you just can't get with USB flash drives.