What kind of time limits were you guys looking at when you ran suicides? At what point do you think suicides cease being productive?
As a coach, I've been toying with my running philosophy. I've often found if I make a habit of pushing for a long string of what I expect to be sprinting drills, players will pace themselves, thus nullifying the effects I desire. I tend to believe the true value of something like a suicide is to enable a player to build their sprinting speed over a semi-extended period of time.
Another running drill I loved and mostly hated at the same time in high school was something we called a Vegas. I'm sure everyone else here has done a variation, only under a different name. We were required to run the width of the court 15 times in one minute (running to one sideline was 1, to the other was 2, so on...). It was doable enough for most of us that we probably could have extended the number to 16, but it was still quite taxing.