Old thread but still worth looking at. The bit Bullseye showed is a notching tool used in better wood shops. The one I have at my club has it's own motor and press. They work great for notching and can be bought in many sizes. I tried to use the one at my wood working club last summer on my last scratch build to cut the notches in the ribs. What I learned right away is you must cut the notches before you cut the ribs out if you want to get the same/correct depth of the notch.
If it is a absolutely a needed thing I can go to the wood shop and take photos and get the names of the manufacturer. Not somethin I feel like doing but I will. The machine we have is something that I'm sure no one could afford just for scratch building planes at home.
I find my scroll saw works for cutting complete kits. I did use the shops band saw on my last build and it was another good choice for cutting.