I've written a script to parse a log buffer, and trigger some action based on the log entries read.
This will allow you to monitor for events on RouterOS itself, and run any specified actions.
You can parse an entry to find IP address, host-name, user name, etc... basically anything the log data contains can be evaluated. It also runs very fast as it uses 'print as-value' to capture log entries into memory.
It can be found on the Wiki here: http://wiki.mikrotik.com/wiki/Log_Parse ... ger_Script
If you have a great parser to extract data from a log, please post it, as it may be useful to others and myself.