I have no idea whether any of this has been proposed before or not, but they are my own ideas.
Turn bounty hunting into an actual profession, with skills. A set of tracking skills could be one example, which somehow allows the bounty hunter to know where the target is within some margin of error (at level 5, perhaps 0% error). Perhaps many actions a player does should leave an electronic trace. In our own modern world, any time you use a credit card, withdraw money from an ATM, use a mobile (or other) phone, send an email, do a google search, etc. your actions are being monitored and traced, and you can be tracked by law enforcement. Banks track you this way in order to repossess cars or planes or boats, and bail bondsmen track their marks this way. So why not have a set of skills mirroring this? Every time a bounty is paid to a player, there is a trace. Every time he buys or sells a ship/module/whatever, or executes a contract, there is a trace. Every time he docks at a station or jumps through a gate, there is a trace. Every time a clone jump is performed, there is a trace. Every time a clone is left somewhere, there is a trace. Every time a line is typed into a chat window somewhere, there is a trace left. And with appropriate skills in these areas (gate tracking, ISK tracking, clone tracking, electronic communications tracking, etc), the guy can be hunted and tracked.
LICENSE TO KILL
Perhaps a license to kill could be issued by CONCORD to the bounty hunter. Either it could be a specific license to kill a specific character, or a general one (of course there would need to be protection from abuses).
The current bounty system is weak in that its consequences are easily avoided by the hunted. For instance, the bounty hunter is only paid some percentage of the value of the ship of the hunted, so the hunted can easily fly cheap ships, or even no ship at all - just a naked pod with no implants. So, the bounty hunter must be given other tools to extract payment from his target. For instance, if the mark only flies around in a naked pod, perhaps ISK could be deducted from his account every time he is podded, and given over to the bounty hunter. Or perhaps we could introduce yet another skill for bounty hunters - bank account hacking or whatever - which would let them somehow electronically steal from the target. Perhaps there could be skills for finding and destroying (or ‘repossessing’) ships owned by the target which are docked ‘safely’ somewhere, destroying clones lying right in their clone vats, etc. Sky could be the limit here.
Now, it is possible the hunted could still evade repercussions, by for instance transferring assets to an alt. There are a number of ways this could be dealt with. Perhaps there is a skill the bounty hunter could learn - ‘freeze assets’ - which would stop the hunted from transferring assets anywhere, for a period of time. Or, perhaps allow asset transfer to other characters, but then THEY THEMSELVES could be legally bounty-hunted (they could receive a warning message before they decide to accept asset transfer).
Perhaps special ships/modules could be used to carry out ‘skip tracing,’ tracking, destruction or ‘repossession’ of assets, etc.
Just some ideas off the top of my head. Discuss.