I'm a woodworker and can make a handle easily enough, but what's the rest of the process like?
You can get knots from:
The Golden Nib
Shavemac
Virginia Sheng, or ACE on eBay.
The Golden Nib 2 Band Finest is a great knot.
Another thing to consider when making a wood handles is how to protect it from water. There are a wide variety of finish materials and techniques available. I prefer using cyanoacrylate as a durable finish.
Where do you get the knot?