No. You shouldn't expect users to run a program that would notice a particular disk drive hasn't been used in X minutes and then power it down. (Although they could if they wanted to... except that there's no way for userspace to know when the drive was most recently used.)
I use noflushd to do userspace powerdowns for internal (ide) drives. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html