Oh, I think "General" is right for OB bonuses on non-weapon items, because it is more powerful to have a +10 on a gauntlet that can be used with any weapon than it is to have a +10 on a weapon where the bonus only applies when using that weapon. It would also be reasonable to disallow such items entirely.
As for "only items that make sense", that's a matter of GM judgment and has a lot of subjectivity and edge cases. I would allow a flute of singing, but the bonus would apply to anyone singing along with the flute rather than the player.lk