Scott,
I'm not quite sure if I follow you?
Whats the advantage of this over just right clicking, sending to external program, editing and saving and then MC will still be pointing to the right file as u've just edited it?
To then update (write the tags back to the file), right click and choose update from tags, always.
This will then give u your files, edited?
Also, just a suggestion - if you find yourself doing a lot of auto colour, auto contrast, etc to your pics, why not use photoshop to create a droplet action, save it as 'Auto Color.exe' - then set it up as one of your external programs to send to.
You can then right click on a file and 'send to/auto colour'.
It'll then just fix the colour for you automatically without having to do anything?