I let you explain openBSD guys why their constant code audit is useless.
And I'm not so definitive about linux's security : if I want a very secured mobile device, I would tend to trust peoples who make security their first concern more than the others.
Today, I don't know well the security level of a minimal debian installation... But on last September, wasn't bash the default shell of debian ?

Anyway, I think you miss the point (and I would be happy this discussion took place on the other topic 5 monthes ago).
I'm not saying "Making OpenBSD run on Neo900 should be a priority"
But "Do you think OpenBSD could run on Neo900 ? OpenBSD community may be happy to be aware an open phone oriented toward security and privacy is about to exist... Furthermore if it's open enough to let them a chance to make their OS run on it"

If this project interests many communities (especially security focused ones), far more peoples could contribute and donate.
From now, I almost didn't heard of Neo900 elsewhere than on this forum. It make me think we probably miss a wide number of potential contributors.