Trek to the Stars Part 3: But what do they actually do?

I have been working on a new project for a little while now(her is Part 1, Part 2, and Part 3), and I have been enjoying working through the ramifications of the rules and setting so far. I am now at the point where I need to start narrowing the field of play. Those who know anything about my design philosophy know that I am firm believer that play should be focused around a central conflict or theme. At heart I am always asking myself, "what do the player characters do in the game?" and, "how do the games rules help encourage that behavior?"

After I set out the mechanical basics of the game, in the last post, I got into a bit of a discussion about the emergent properties of play. During the discussion I came to a few conclusions about the setting and system. The system is heavily focused on choice(in the dice you choose to keep) and precision(you crit upon getting the exact target number). The system also focuses on pushing yourself beyond the normal limits(you can increase the difficulty to gain extra effect and you can spend character points to increase your number of rolled or kept dice) and seeking to do the impossible(failure grants bigger XP rewards than success). The way XP works also tends to lead to player proactivity and focus on choice(the only way to improve a skill is to find a legitimate use for the skill).

The setting, what there is of it, also has some implications. In discussing it, I realized that there were a couple of themes and genres running through the potential setting. There is big frontier feel to the setting so far. Humanity has spread beyond earth and have settled all throughout the solar system. This seems to indicate that in general populations of places will be lower per square mile than current populations. Also there are the ideas of exploration and expansion, with travel being somewhat slow and people living in the Kuiper belt and all. The expansion of the human form and ideas about what it means to be human(or sapient) leads to another area for expansion, exploration, and defining the frontier.  So I see several possible campaign frameworks that would work within  this setting(as it stands). I found this thread on rpg.net to be of much use in working out some basic campaign ides.

Potential campaign ideas:

1. You play as frontiersmen who must stand between barbarity and civilization. I see this as anywhere from The Man Who Shot Liberty Valance to The Magnificent Seven, but in space. The focus would be on the nature of using force to protect the innocent. I could see things on the Martian frontier going this route, the miners on Mercury would also be a fine place for it, as could the tiny colonies out past Pluto. 
2. A game where you play roving lawmen who deliver mail and justice. Think of it as Dogs in the Vineyard throughout the solar system, or like the second half of Tombstone where Wyatt Earp is hunting down Cowboys with fiery vengeance. You could play as members of a federal law enforcement service keeping the peace throughout the state, or as members of something like Interpol, but for the whole solar system. You would spend most of the game hunting fugitives, terrorists, and smugglers.
3. the political game, where you are back in civilization and dealing with the players and movers and shakers. Whether it is the Genetically Enhanced rulers of the Saturn Baronies or the infighting within the libertarian Free Republic of Rand(still working on names), the idea of this game is to play the elite in their fight for control of power and influence. It is very Dune-esque in my mind. 
4. Rebels still fighting the last war after it has been over for five years or more. I am unsure as to what the war was about, but my view of the setting as a western requires some sort of war to have ended recently. Basically during the war a number of states established a stronger power base and subsumed several smaller nations and rebel states. In this you would play the remnants of the armies that fought in the war. You may have lost nearly everything, but you still have your pride and your will not give up.
5. You play settlers/miners out on the fringe, this would be mostly about dealing with a small community and the struggles of making a living on the edge of livability. The game would focus in interpersonal problems and dealing with unexpected problems. External threats would be meteor collisions, radiation leaks, bandits/pirates, and machinery failure. 
6. Traders/performers/travelling scrap collectors and repair men(for big stuff that is hard for folks to repair on their own) travelling the routes across the solar system would be pretty fun as well. You would travel from place to place trying to make a living through your skills and wits. 
7. Missionaries or travelling priests ministering to the masses throughout the system. I think this would be an interesting one to work with. Again it would be a bit like Dogs in the Vineyard, though with less shooting.  This is a campaign type that I have not seen much of in many games, so working on this would be kind of cutting a new path. That does appeal. Also it would allow for some interesting conflicts related to religion and its role in civilization.
8. The love boat in space, seriously, think about it. It would be an awesome game. 
9. Planetary surveyors on a mission to detail the lands and resources of a region, I think it would be neat to play interplanetary Luis and Clark. I have some ideas on how I would do it as well, so that is a thing. 
10. Artifact investigation and recovery teams. After the last war there were many historical artifacts missing after raids and pillaging. Think The Monument's Men but in space. 
11. Journalists seeking to get the scoop on various big incidents is another type of campaign you don't see all that much in games(or at least, I haven't seen it much). I am unsure how to go about doing it, but it would be a neat campaign framework, or at least a solid character concept.

So those are the basic campaign ideas I had for this project. What do you think? Is there an area you see that I didn't cover? Are there some ideas that you think would just be terrible in practice? I would love to hear your thoughts, comments, and concerns.