Working on a new jig

So yesterday, I started working on a jig that rough cuts the back profile of the neck.  It basically hangs the guitar neck over a dado blade and with incremental movements from side to side it cuts the curved profile of the neck.  I for the life of me can't remember where I saw a picture of one in use, but it sure appeared to be a great tool that would get tons of use in the shop.  Right now I route the neck blank down to the thickness I want it, then pull out the rasps and files and go to work on the contour of the neck.  If this jig works as I hope it does it will remove a ton of time that I currently spend shaping.  I'm about half way finished with it, but it should be ready to try out tonight.  I'll post some pics of it.  Like I said, I don't remember where this idea came from and I only remember seeing one picture of the jig in operation.  It could be that it won't work at all cause I didn't remember some hugely important element, or more likely, didn't see some hugely important element in the picture.  Oh well, it's still fun to build things and try them out.