well, a long enough exposure can blur people out, something like a Big Stopper or something can get you 30-second exposures.
@OP, what are you shooting, E6 pos or C41 negs? Negs have great DR, but positive films have much much less, get it out by 2 stops or more and you're either all white or all black. Definitely keep the grads, going even further to reverse-grads will help a lot with sunsets. Also, a spotmeter can be very useful in determining correct exposure for landscapes on positive film.