Chris Spracklen has devised a method of developing an (virtual) HDR image from a single RAW file. The method involves taking
a number of exposures of the single file in Adobe Camera Raw and then processing these exposures in HDR software.
I have applied this method to an image series I posted on May 26, 2008. The RAW file for the upper image in the
series below is the one I worked on:

http://www.pbase.com/drjaysel/image/100702654

The shadow areas clearly lost a great deal of detail in the original image. These details are restored in the HDR image. Overall
I like the HDR image much better, but that's my personal preference. Perhaps I could have processed the single file
much better in 2008 for a fairer comparison.

Anyway, I wound up using seven virtual exposures in developing the HDR. Thanks very much to Chris for all of his help,
although unfortunately he is not to be held responsible for any defects in the final result! This method is clearly
ingenious and also very useful if one hasn't shot multiple exposures in the field.