You don't actually need it to be a service. You can just run the monitoring portion in an infinte loop:

while(1) {
   my $result = monitor_object();
   display_result($result);
}
[download]

Though I suspect making it a service will make your monitoring script use less system resources.

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated