Detachable Droid Head

Made from scratch.

Close-fitting android neck connector with a matching head connection. No issues on vanilla/gen3 bodies, but Bibo+ and some Bibo-based bodies use a larger neck connector that will clip at extreme angles. I recommend just not turning the neck too much (there's no head anyways).

Dual dyes for both pieces.

Some races (like viera) will still have a visible neck connector when using the body piece, so there's an option to hide it with the Emperor's New Hat.
Male roegadyn and hrothgar have very tight spacing within the head, so part of the inner mouth/tongue are visible when using the body piece. Custom posing tools should be able to move it out of view.