Now, I don't know in which state the development of SpaceVenture is at the moment, but considering we don't have to know any idea on how long the project will continue and how long overdue it is, I do think it could be smart to release the current beta build to all of the backers. Especially, if the current development of the save function is going to take longer still.
If anyone is worried about the "exclusivity" of the beta to a specific set of backers, I do believe the year we have had the access is more than enough to cover it, especially considering that we haven't had an update of the beta for a long time.
So, I don't know. Maybe it could be smart to release the build to all the backers. It could show some good faith, perhaps even alleviate the current mood at the Kickstarter forums. That place hasn't been pretty in a good while.