Both of @Mr Winberg's claims above are true, provided the following disclaimer is used with the stack size changes: "... provided all other variables remain the same...", and are certainly backed up by both calculations and real-world tournament data (compiled by myself and many others). The correlation of stack size (or total chips in play) to event length is not linear, regardless of player styles.This is a forum and some people read these posts to learn. .../snip/... A common misconception is that e.g. "If we double the stack sizes, the tourney length doubles". This isn't true..../snip/... Similarly, adding 33% to the stacks will not lengthen the tournament by 33%, but maybe by a level. Calculate it or experience it, the results will be the same.
But the bottom (and marvelously interesting) line here is that there are multiple ways to skin a tournament cat to accomplish many differing goals (including ways to make them appealing to primarily cash game players, for you tourney naysayers).
Just like there are many types of horrible tourney structures, there are many types of excellent tourney structures that produce the desired length / play / goals of each one.