Some of you may be familiar with the camp game Assassin. The gist of it is, each player is given another player that they must assassinate (being a game for teenagers, this usually involves finding them in a room alone and screaming something fun like "BANG!"). Upon the successful assassination of another player, you then take their target to be your own until finally, there is one person left playing, having left a path of murder and death in their wake. It's sort of like the playtime version of Koushun Takami's Battle Royale.
That's the premise of this idea as well. While playing your usual thing of killing aliens and crafting things, if you do something illegal, a bounty will be put on your head. Other players can then collect this bounty by tracking you down and killing you real nice like. A small twist is that the space mafia (everything become scifi when you prepend "space" to it) can take out hits on prominent enemies and bounty hunters.
Okay, that's all well and good, but what does this have to do with the massive boardgame concept? Well, once you have a bounty on your head, your character never actually logs off - he can be located and murdered even when you aren't controlling him. So finding proper hiding spots is a must. You could, for example, hide out in a gang controlled hideout - which should be pretty safe, assuming the bounty hunter doesn't trick some other player into letting him in.
How does a bounty hunter locate his prey? By process of deduction. Each node on the map will remember the last, let's say, two hundred people that went through it. By asking NPCs, they could potentially give you information. Depending on your skills as a bounty hunter and on the NPC you ask, you could simply receive information that the prey was at this particular node within the last hour. Or you could find out what exact time they were there, and even which direction they left from (putting a big arrow on the map that grows smaller depending on how long it has been).
Players can even get in on the action. They may notice a player with a bounty on their head. They can then run over to a police station and report it, which will increase the quality of knowledge bounty hunters can get from that location. They could also, of course, just report straight to the bounty hunter himself for a reward. When a city or planet is aware that a criminal is on the planet, they might make it harder for that player to leave without being arrested.
By going around to the different nodes and asking around, you should be able to track the bounty down to a specific planet or location. You can even realize a pattern of movement and figure out where the bounty is going ahead of time and cut him off. But remember that landing and asking for directions takes time that the bounty doesn't have to waste, so while you are looking for him, he could potentially be moving further and further away. That's why it's important to see where he has been and potentially where he is going, so you can get there first and set a trap.
Star Wars Galaxies had a bounty hunting system in place, but it had very little in the ways of intelligence gathering and outsmarting enemy players. Making travel take time means that someone can actually figure out where you are going before you get there. It means that information is not outdated the second you get it. By plotting this information across the map, you can see patterns emerge. You can see that this player has returned to planet X four times in the past hour. You can see that his trade route goes from planet Y to planet Z. With actual intelligence gathering, being a bounty hunter becomes a matter of a quick wit and deductive reasoning rather than pure strength and luck.