I was just recently working on a pile of high res character stills for print and got frustrated constantly adjusting 4 or 5 lights to get my rim lighting exactly where I wanted it on the character.  So, I dredged up an old trick I used to use way back in the 90's (I know I've been doing this a long time) using falloff maps.  I thought I would record a video for everyone.  I looked around and saw lots of posts of people saying you could do rimlights with falloff maps but no good examples of how.  And specifically I wanted to make them relatively controllable which adds a twist.

As a friend just pointed out, (Wayne I'm looking at you) don't consider this a replacement for using actual lights for rim lighting in all situations.  For example if someone else is doing the compositing they may have something to say about this.  Also quite frankly this isn't faster then traditional lighting in all circumstances.  its just another tool in the toolbox.  Enjoy.  

Also I'm sorry the video of me is over part of the UI I edit for a short while.  I describe what I am doing though so you should be able to figure it out.