I'm contemplating writing an NAnt task for LLBLGen that would run at the end of a generation. I know there is already a compiler there, but with NAnt you could set it up to do anything you can do with NAnt.
Basically, I would make it so that this task could generate the build file for you and then run that build file. I'd probably steal Frans' idea of placing comment areas in the build file that define user area build code so that if the task runs into those comment areas, it won't overwrite any other things you had placed in the build file.
Would that be something anyone would be interested in?