For those interested in customizing the email response templates, here is a list of the current variables that are exposed.
HOST
USER
TRIGGERS
JOB_ID
JOB_PID
JOB_PGRP
JOB_USER
JOB_DOMAIN
JOB_STATUS
JOB_PRIORITY
JOB_NAME
JOB_CLUSTER
JOB_CPUS
JOB_TYPE
JOB_PROTOTYPE
JOB_REQUIREMENTS
JOB_RESTRICTIONS
JOB_FLAGS
JOB_LABEL
JOB_ACCOUNT
JOB_LOCALORDER
JOB_GLOBALORDER
JOB_GROUPS
JOB_OMITGROUPS
JOB_HOSTS
JOB_OMITHOSTS
JOB_KIND
JOB_HOSTORDER
JOB_TIMEOUT
JOB_DATA
JOB_TIMESUBMIT
JOB_TIMESTART
JOB_TIMECOMPLETE
JOB_TIMEELAPSED
JOB_PACKAGE
WORK_NAME
WORK_HOST
WORK_STATUS
WORK_PID
WORK_SUBID
WORK_ADDRESS
SUBJOB_ID
SUBJOB_STATUS
SUBJOB_PID
SUBJOB_ADDRESS