We already had a backup of the GoBe Productive sources. GoBe people planned to release it under the GPL or some other open source license, but they needed someone to clean it up from non-open-source component that they did not own. At the time, no one took the time to work on this. We need a developer (or a team) with the skills and time to handle this. As long as the sourcecode is not cleaned, nothing will happen.
I don't think purchasing the Be sourcecode would help us in any way. As the people who worked at Zeta can tell you (some of them are Haiku contributors now), the code is generally quite messy (they were rushing to get something out at the time), and it is also a lot out of date. The hardware we run on has changed, we made a lot of improvements and clarifications to the BeAPI, and Haiku doesn't have many bugs that BeOS did. Also, the BeOS code has similar issues to the GoBe Productive one: even if someone purchased it, they couldn't relicense it under a free software license until aafter cleaning it from dependencies on 3rd-party software. All of this only for a 15 years old code that probably wouldn't compile on any modern compiler. It would be a waste of time to do this now.
I can't comment on how to become an Haiku, inc. board member, as I've never been one myself. What I can tell is there is a public mailing list where there is surprisingly few people active. You could send an e-mail there and offer your help, or you could join the list and take part in important discussions about how the money is going to be spent (for example in the past weeks there was a contract proposal from Waddlesplash for a development contract this summer). The final vote is private by the board members, but the discussion is public. Maybe starting to contribute there is a good way to get involved in running Haiku, inc?