I assume that by neck You mean the fretboard?
Staining the FB black is relatively easy, but relatively time consuming=expensive.
What is it now?
Rosewood or maple?
If OTOH You want an ebony FB, just the FB is removed and replaced, no need for a new neck. Not cheap, but perfectly doable.
Removing the wings from the center block can be done as well, but pretty pointless unless a NT neck is totally trashed.