Derek, on my opinion you could do like this:
The game would be like this:
1.-Game will have Engstrom class and it support classes (ships, fighters, ground vehicles).
1.1-The ship and support classes things will be EXACTLY like they were, or how they werent suposed to be (in the case this ship was not fully made on previous games because the lack of time, money or whateaver).
1.2-You will be able to walk into first person mode inside this ship
2-Game will have ONE type of star station
2.1-The starstation will have the same amount of detail (or more if the star station was not fully realised, because of the lack of time, money or whateaver)
2.2-Player is able to walk first person inside the star station.
3-Player is not able to walk on a planet on fps mode.
You would make an kickstarter (or whateaver site you prefer) and ask for the ENTIRE money needed to produce this thing (this includes the money kickstarter will get from you and the money you will use to give prizes to users that back your project).
Do you know the DCS simulator series? Your game could be some sort of the scifi version of DCS, super mega ultra detailed but with mostly one ship.
Then IF your game is backed, after you release it, you try again, now doing some planetary vehicles and on this specific version finally including planetary fps.
Then newer expansions would be new spaceships or new pack with various planetary vehicles.
The point of this idea is to save money and time by making only one ship (and his subships), and also with it because to really focus on this ship and make it with extreme detail. Also with kickstarter you just make the game when and if you discover people liked it
