The reason I want an off position is because I have 3 pickups. I want the seven options you can get with 3 pickups in both parallel and series. The way I've figured to do this is have the 5-way switch with the positions mentioned above and then have a separate on/off switch for the middle pickup and a switch to put it in series or in parallel.
If anyone has a better idea for this, it would be greatly appreciated.
Thanks guys, for spending your time answering my question.
In that case, I'd use the 4-way diagram shown above, minus the volume and tone controls. You'd then wire this into a 'binary tree' arrangement which uses two switches to give you the 4-way selection, middle pickup, 4-way in parallel with the middle, 4-way in series with the middle. The 'off' position could be a bit awkward to wire if you also have a series/parallel on the middle pickup.
This is a variation on John Atchley's "S-tastic"mod by Hastings ('jhng"). It does what you want, using 2 push/pull pots to control the mid pup in series/parallel, while pulling both pots gives "middle alone", thereby accomplishing turning the 5-way off, as you desire. A third push pot is used to phase the middle pup, but that could be eliminated if you don't want ooP sounds.
One of the tone controls is for the mid only in series or alone, while the other controls N and B.
This design has some nice features, including maintaining the stock look. You should take a close look at it.