I was under the impression this feature was complete. I have spoken to the developers and I think we have come up with a great solution.
Our plan is to add options in General Settings>Bible for selecting Default Bible. Similar to what you have for selecting a default script. The Options will be "Specific Bible" and "Most Recent Bible".
The current behavior in B65 will not change, but with these new settings, MediaShout will revert to the Default Bible setting the next time it is launched.