The three virtues of a programmer: Laziness, Impatience, and Hubris. – Larry Wall
It's possible to script custom movers in UnrealEd 3, just as it was in UnrealEd 2. Whether they are actually required or not – that's another question: watch this space! :D
You need to write a script yourself, compile it and put it in the ini file as an EditPackage (same as custom brushbuilders).
To add a mover of a custom class:
this would be a good place to post scripts...
SuperApe: Perhaps this needs a to be merged with Scripting Movers?