This snippet will show a nicks clones on the channel when a clone joins. Requires mIRC v6.16.

on !*:join:#:{
  var %clones, %i = 1
  while ($ialchan($wildsite,$chan,%i).nick) {
    %clones = %clones $nick($chan,$v1).pnick
    inc %i
  }
  if ($numtok(%clones,32) > 1) echo $color(info) -bfilrt $chan Clones ( $+ $calc($ialchan($wildsite,$chan,0) - 1) $+ ): $remtok(%clones,$nick,1,32)
}