Or you could change the look of msn completley and go for a new skin:
http://www.messenger-skins.net/
This might change the colour of other away messages so you can see them better.
But tbh im not quite sure, youll have to wait for someone else to see if there is a quick solution.
About the colour fader, there should be a plugin
Here, last time i checked there was
Edit: Are you sure on the preferences screen, you havent moved the "Transparency" cursor ?
Plus! > Prefences > Contact List > Transparency Effect.
Make sure this is on "0%".