I've asked about this myself and never really got a satisfactory answer, but the best I got was advice to grab a group of friends and go to the last known system the were in when last spotted, split up to the usual haunts (Nav Beacon, RESs, USSs, etc.) then call out when the target is spotted and converge on his/her location.
this has always been my approach to finding players in systems also. make sure you have a good set of scanners and are geared for a good fight though. people in that top 5 bounty slots usually don't play well with others obviously
