Actually, gemelli, penne, and fusilli (to just take the three I'm familiar with) look nothing like the strozzapreti I'm famililar with, and the three are very different from each other as well. Or did you mean "substitute" in the sense of "these are good served with a similar sauce"?
Because the shape of the pasta is often dependent on the rest of the dish. You wouldn't, for example, serve cappellini with a heavy bolognese sauce (you could, but the two are not particularly well matched). Similarly, you wouldn't make large shells unless you were going to stuff them with cheese or something.
Sorry if I've misinterpreted your comment!
Also, I've not seen it with two T's in "preti." Did you find that in an Italian dictionary? Just curious!