This snippet checks users on join and if there are 2 or more with the same !@host.domain.com it changes their nicknames' color. If there are more than 14 pairs of clones then the nicknames' colors will start to repeat. It also has a popup which allows you to kick/ban clones easier. Just try it...

ON *:JOIN:#:{
  var %clone = 1
  if ($ialchan($wildsite,#,0) > 1) && ($($+(%,clones,.,$wildsite,.,$chan,.,$network),2) == $null) {
    if ($($+(%,colors,.,$chan,.,$network),2) == $null) { 
      set $+(%,colors,.,$chan,.,$network) 2 
      set $+(%,clones,.,$wildsite,.,$chan,.,$network) $ialchan($wildsite,#,0) $($+(%,colors,.,$chan,.,$network),2)
      while %clone <= $ialchan($wildsite,#,0) {
        cline $gettok($($+(%,clones,.,$wildsite,.,$chan,.,$network),2),2,32) # $ialchan($wildsite,#,%clone).nick 
        inc %clone
      }    
    }    
    elseif ($($+(%,colors,.,$chan,.,$network),2) != $null) && ($($+(%,colors,.,$chan,.,$network),2) < 15) {
      inc $+(%,colors,.,$chan,.,$network)
      set $+(%,clones,.,$wildsite,.,$chan,.,$network) $ialchan($wildsite,#,0) $($+(%,colors,.,$chan,.,$network),2)
      while %clone <= $ialchan($wildsite,#,0) {
        cline $gettok($($+(%,clones,.,$wildsite,.,$chan,.,$network),2),2,32) # $ialchan($wildsite,#,%clone).nick 
        inc %clone
      }
    }
    elseif ($($+(%,colors,.,$chan,.,$network),2) != $null) && ($($+(%,colors,.,$chan,.,$network),2) > 15) {
      set $+(%,colors,.,$chan,.,$network) 2 
      set $+(%,clones,.,$wildsite,.,$chan,.,$network) $ialchan($wildsite,#,0) $($+(%,colors,.,$chan,.,$network),2)
      while %clone <= $ialchan($wildsite,#,0) {
        cline $gettok($($+(%,clones,.,$wildsite,.,$chan,.,$network),2),2,32) # $ialchan($wildsite,#,%clone).nick 
        inc %clone
      }    
    }    
  }
  elseif ($ialchan($wildsite,#,0) > 1) && ($($+(%,clones,.,$wildsite,.,$chan,.,$network),2) != $null) {
    set $+(%,clones,.,$wildsite,.,$chan,.,$network) $ialchan($wildsite,#,0) $gettok($($+(%,clones,.,$wildsite,.,$chan,.,$network),2),2,32)
    while %clone <= $ialchan($wildsite,#,0) {
      cline $gettok($($+(%,clones,.,$wildsite,.,$chan,.,$network),2),2,32) # $ialchan($wildsite,#,%clone).nick 
      inc %clone
    }
  }
}
menu nicklist {
  $iif(($me isop #), Ban clones):{
    set %reason $?="Reason ?"
    if ($ialchan($address($1,2),#,0) > 1) { 
      var %nicks = 1
      var %addrs = ($ialchan($address($1,2),#,0)
      while $ialchan($address($1,2),#,%nicks) >= %addrs {
        if (%reason != $null) .ban -k $chan $ialchan($address($1,2),#,%nicks).nick 2 %reason | unset $+(%,clones,.,$address($1,2),.,$chan,.,$network)
        inc %nicks
      }
      dec $+(%,colors,.,$chan,.,$network)
    }
    elseif ($ialchan($address($1,2),#,0) == 1) { 
      if (%reason != $null) .ban -k $chan $1 2 %reason
    }
  }
}
ON *:DISCONNECT:{ unset $+(%,clones,.,*,.,*,.,$network) | unset $+(%,colors,.,*,.,$network) }
ON me:*:PART:#:{ unset $+(%,clones,.,*,.,*,.,$network) | unset $+(%,colors,.,$chan,.,$network) }
ON *:PART:#:{ if ($($+(%,clones,.,$address($nick,2),.,$chan,.,$network),2) != $null) && ($ialchan($address($nick,2),#,0) == 1) { dec $+(%,colors,.,$chan,.,$network) | unset $+(%,clones,.,$address($nick,2),.,$chan,.,$network) } }
ON *:KICK:#:{ if ($($+(%,clones,.,$address($knick,2),.,$chan,.,$network),2) != $null) && ($ialchan($address($knick,2),#,0) == 1)  { dec $+(%,colors,.,$chan,.,$network) | unset $+(%,clones,.,$address($knick,2),.,$chan,.,$network) } }
on me:*:join:#:{ 
  inc $+(%,who,.,$cid,#) 
  .timer 1 5 who # 
} 
raw 352:*:{ if ($($+(%,who,.,$cid,$2),2)) halt }
raw 315:*:{ halt }