I am looking for the same thing but I am looking for this type of player finder where they draw a line from the crosshair to the player you desired like in this video by team avo:http://www.youtube.com/watch?v=4ZTgG1MUOdc.
VERY OLD thread, but I don't condone hack clients but Nodus is a good way to cheat on PvP and find hidden chests, x-rays, traer (lines of players) even a radar which gives you notifications if someone is in 200-400 blocks of you, aimbots alot of stuff it can do.
Ive been looking for something to find players in a anarchy server. its a FTB Direwolf20 (Modded) server and this group of people have griefed my team 3 times in a row using something. for ex, a half an hour of moving while they kept attacking us, we had salvaged lots of stuff and moved to Y level 8 5000 blocks away from our old base. after that half an hour, were dont moving and i hear digging above and in comes them with nukes and other stuff.....getting really ed, this has happened 3 times now