How do I save Lightroom image edits in source file?

Question

My experience with the trial version of lightroom is very positive in terms of the convenient and powerful capabilities for editing images and the associated metadata.  But I can't find a way to save the "develop" edits to images into the source file for the photo I am working with.  So far, I am able to save the metadata into the file but not the image editing.  From what I read, I fear this is not possible without silly round about exporting to new files then copying / moving multiple copies around, etc. Without this ability, I am pretty sure I will not purchase lightroom and will miss out on all the powerful features.  Without an OPTION that turns on the equivalent of a SAVE button, managing my photos collection would be a nightmare. 
So my question is: How do I save the edited (i.e., developed) version of a photo back into the same file where the original photo was stored?
Please, please spare me all the reponses telling me how stupid I am for wanting to do this and that the cognisenti and professionals would NEVER do this.    But please just tell me there is a secret place to turn on this option in lightroom.
Thanks in advance.

Answer 1

I had the same requirement to save in JPEGs files all non-metadata edits performed in Lightroom, in order to share modified pictures without duplicating files. By the way, I think it’s going to be more and more required by casual Lightroom users, as people get used to instant photo sharing in many situations where quantity matters more than quality
Here’s a nearly automatic (at least, scalable) solution that works, although it slightly lowers the quality by re-compressing the original pictures.
Once for all:
Download and install the wonderful Lightroom plugin “jf Run Any Command”, provided as donationware by Jeffrey Friedl here: http://regex.info/blog/lightroom-goodies/run-any-command. This “export filter” plugin allows you to run a command of your choice with each exported file, as part of the export while it’s going on. (You may also browse Jeffrey’s blog to find many other useful and beautiful things.)
In Lightroom, pre-define an export settings as follows:
Export to the hard drive, to the original picture folder, without adding the exported file to the catalog
Name the exported file “EXPORTED-{Filename}” (or anything different from the original file name)
JPEG format, 76% quality (see An Analysis of Lightroom JPEG Export Quality Settings at http://regex.info/blog/lightroom-goodies/jpeg-quality)
Keep all metadata
Here’s the interesting part, the Run Any Command settings:
Command to execute for each exported picture: copy "{FILE}" "{Path}\{LIBRARYFILENAME}" (this replaces the original file with a copy of the exported file)
Command to execute upon export completion: del {FILES} (this deletes all exported files).
NB: One could wonder why not directly export with the original file name and silently replace the original files (I believe Lightroom would allow this). It’s just a matter of error handling: in case the export goes wrong, no original file is changed at all.
The easy part: each time you want to save edits:
In Lightroom, select the pictures to save, and export them with the pre-defined settings. You're almost done. The JPEG files are ok, but inside Lightroom you see the modification effects doubled, as their specifications remain in the catalog database and they apply on modified JPEG instead of the original files.
While the entire set of "saved" pictures is still selected, in the Develop module switch Autosync on and click Reinit to erase all modification specifications from the catalog for all pictures, then press CTRL-S to write down to disk any metadata updated by Lightroom -and accept if required to confirm that Lightroom values should replace externally set values.
Stephane
PS: Papa Ben, I'm curious about the decision you  finally made