Aha! Nope it's not disabled, I'll have to investigate your other suggestions, this just showed up in the slow log - we had improved our mysql setup so it was faster and eximstats was now escaping the time limit
So still running a day or two later after disabled.
# User@Host: eximstats[eximstats] @ localhost 
# Query_time: 1.562439 Lock_time: 0.000080 Rows_sent: 0 Rows_examined: 3970
update smtp INNER JOIN sends ON (sends.msgid=smtp.msgid) set smtp.processed=3 where smtp.transport_is_remote=1 and sends.user IN ('-remote-','root','mailman') and smtp.processed=0;
 [2012-07-28 15:27:47 -0400] [Cpanel::TailWatch::Utils::EnableDisable]  [2012-07-28 15:27:47 -0400] [main]
Cpanel::TailWatch::Eximstats was successfully disabled
ps. Does the eximstats database table have all the indexes it should have for best performance?