Hey Dom,
I agree this would be a great feature. It's a bit tricky though as I need to find a way to represent the randomness in the graph without just constantly redrawing it. It's definitely on my list of things I'd like to add though. In the meantime you can get it sort of working using generators, variables and a pseudo random number generating algorithm. For example the attached program to applies some "random" offset to a note's velocity using the "rand" variable. And you can control how fast the random numbers will change by setting the period of the "speedOfRand" generator.
Give it a shot and let me know if it accomplishes what you were looking for.
Rob