Probably the 'cleanest' way to do this would be to sub-class the object's class, and a create a method that does the logging and calls the parent's method. Something like this:

package Sub::Object;
use base qw(Orig::Obj);

sub doSomething { 
  my $self = shift @_;

  $myFunkyLogMachine->Log("hi!");
  my $value =  $self->SUPER::doSomething(@_);
  $myFunkyLogMachine->Log("hi!");

  return $value;
}
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Then you would just use Sub::Object in place of Orig::Obj and you'd get the logging.