Interesting trivia: staggered drive spin-up is an optional part of the SATA II spec. Unlike most SCSI drives, though, it’s not controlled through a jumper. Instead, it uses one pin on the SATA power connector. If pin 11 is floating, then the drive is supposed to wait to start spinning.
Apparently the 650W power supply in my new server only provides enough current to spin up 10 drives at once, because adding an 11th drive makes it turn off on its own immediately. Sigh. I wonder if anyone makes delayed-spin SATA power dongles?