OTRS has some reporting.. after seeing this post I installed OTRS yesterday (Much easier than getting rt setup I might add)
This morning at Login I was immediately greeted by some automated reports.
Stat# / Title / Description
10001 Changes of status in a monthly overview Monthly overview, which reports status changes per day of a selected month.
10002 New Tickets Total number of new tickets per day and queue which have been created during the last month.
10003 Overview about all tickets in the system Current state of all tickets in the system without time restrictions.
OTRS does have SLA timing you can configure.
First Response Time (minutes): 0 = no escalation - 24 hours = 1440 minutes
Update Time (minutes): 0 = no escalation - 24 hours = 1440 minutes
Solution Time (minutes): 0 = no escalation - 24 hours = 1440 minutes
if OTRS doesn't do it for, you give RT (Request Tracker) a shot.