Well, it's been half a year and I only just found this thread and signed up to the forums, but I do in fact have a poseable Bohrok neck design to share. I don't remember for sure whether this was originally mine, but after searching online for Bohrok necks the only one I could find tried to maintain the original gear functionality at the loss of neck range, and I'm fairly certain I made this version specifically because I couldn't approve of that range loss.
The head removed, with neck still attached beneath. Sadly, the axle-pin is in exactly the hole where the towball pin holding the rubber band would go, so that's one less similarity with the original. A 12-tooth gear on the back emulates the original neck piece's attachment point.
The neck removed from the head. I would have made the axle-pin run through both sides but I didn't have the pieces at the time to do that and maintain friction.
The base of the neck attaches via the newer ball joint model, with the axle hole going all the way through. The 3-axle in the middle has been removed to make room for the neck.
The neck was far from the only thing I modified about this; I fiddled with the limb arrangement for quite a while to get them to have middle joints, start with the shoulder/knee joints the right way around, and still fold into a ball properly. I also added the third shield/hand/thing on the back to fill the hole left by the removed gear lever.
This was going to be more detailed, but apparently new users only get three images in a post. Seems fair, I suppose; I've seen forums with far more restrictive newbie rules.
EDIT: Anyone have some ideas for Skakdi skull masks? There are only eight that work with the skull on account of the teeth, and six are rubber monstrosities. (Also I'm out of pictures and I have a krana-fitting head that's really cool but I can't double-post.)