*sigh* I've heard it argued by theologists that if the flood was localized, god would have just told Noah to move, instead of telling him to build a big ship, unless of course he planned to take Noah fishing or something. There are also great flood myths from the Aztecs, or was it the Myans, I forget which now.
Its been suggested that when the asteroid of doomyness struck the earth that it caused massive wide scale flooding, not enough to wash over the Himalayas, but enough to bury large sections of the globe under massive tsunamis. This could also coincided with the fire and flooding that supposedly comes at the end of Ragnarok, as well as the whole fire and flood thing that happens in the myths of several Native American tribes. While there isn't enough water on earth to make water world. I do believe that large sections of the world could be hit with massive flooding at once. Though there is a theory that such an event could have caused massive changes to the earths landscape. Mount St Helens for example took mere minutes to radically alter the environment around it when it erupted.
And now I'll continue on my jungle primordial kick...time to dance!