Warmoth is a great source for replacement necks for telecasters. They also sell bodies, and enough accessories to build a Telecaster exclusively through them. In fact, here are some who have done just that.
You can custom order a neck with the features that you want, or you can look through their showcase and choose one already made, either finished or unfinished. They will drill the neck for any size tuner that they sell, at no additional cost.
I bought a neck from Warmoth for my modified Telecaster project, and am very happy with it. I ordered one from their showcase, a flame-maple Vintage-Modern model with Warmoth's patented compound radius. It is the "standard thin" contour, the nut width is 1 11/16 inches, and it has stainless steel frets and a clear gloss finish. A beautiful piece of wood. The frets are well-dressed, and the neck edges are very smooth. The neck arrived well packed and in perfect condition on my doorstep, within a week. I had to sand a little finish off of the neck cavity on my Tele's body to get it to bolt up, but that was Fender's fault, not Warmoth's.
The compound radius idea is great, as it allows you to set your action much lower without buzzing. It also makes chords really easy to grip, while keeping twelfth-fret and up playing comfortable.
Definitely consider Warmoth if you are looking for a replacement guitar neck.