One method of funding Star Citizen post launch is the same method that can be reasonably argued to have played a significant role in securing large amounts of funding to the present.
...Life Time Insurance...
Purchasing Life Time Insurance on a ship*, post launch, gives players a feeling of permanent ownership they wouldn't otherwise have. It has already shown its value in massively increasing funding of the game, and would therefore be a reasonable avenue to explore additional funding of the game post launch.
*This post only covers the insurance contract not the initial ship.
A significant hurdle to Post Launch LTI, is its effect on existing backers. This hurdle would have to be handled in a very careful and respectful way to avoid damaging the game post launch.
Many existing backers only funded larger amounts into the game in return for the special "thank you" of a concept that was promised not to exist in the later game.
If post launch LTI invalidates any reason at all, to of backed the game early, then it undermines the trust of many existing backers.
Post launch implementation of LTI would need to respect early backers, by making the early backers pledges more valuable when compared to a post launch LTI purchase.
I think this could be done in basically two broad ways;
Implement Post Launch LTI such that it is not so reasonable when compared to Pre Launch LTI pledges.
Modify Pre Launch LTI pledges, such that they become retrospectively more valuable compared to Post Launch LTI pledges.
I would personally favor the second method for important flexibility reasons.
The first methods simplest implementation, would be increasing the relative cost of Post launch L.T.I, for example a Gladius concept cost around $100 pre launch, but would cost $150 or so post launch.
A significant problem with this is it would be forever governed by the pre Launch LTI price -rather a lot of money for a digital spaceship when compared to other games, and much harder to make a sale when it has lost its uniqueness that it held pre launch.
The second method could however be implemented in ways that allow flexibility in LTI pricing to cater to the future changing ups and downs of funding SC.
One method within this retrospective change branch, is to treat the early pledges as a pool of flexible funds that can, with provision of Token allowances, be allowed to be applied to the prices of post launch LTI ships.
Now if in the year 2020 a Gladius Life Time Insurance contract costs $50, the 2014 backers funds of $100 can be, with the usage of the 2020 token, be applied to the $50 Gladius as well as a couple of $25 Aurora LTI contracts.
The original backer now has been rewarded for backing early by having greater purchase power.
These are just 2 ideas of potentially many variations that do not have to be strictly applied in the present or retrospectively. These 2 ideas increase the "value" of the original pledge but do not cover the "uniqueness" of the original pledge.
Post Launch LTI would however only be the cost of the insurance contract, the ship would not be included, and would have to be acquired preferably in game, and legally checked out before the contract was applied.
Therefore the early pledges uniqueness could be argued to come from the provision of a ship plus the insurance contract.
Funding for Star Citizen is important in the future to provide development updates, new game mechanics, new content, to retain critical Dev talent, and to keep the future PU servers running.
The notion of Life Time Insurance sells well, and could potentially provide a very significant additional revenue stream in the future.