Back before I got smart and just made a Blender plugin, I decided I was going to make my own 3D modeller.
I was an idiot, but whatever.
The good thing, is it worked, even with the fact that I was far less 3D savvy at that point.
Placing vertices was based on view and snaps to nodes already placed. Normals automatically generated (Visible in pane on the right). Triangles were placed clockwise in order to be culled "correctly".
Either way, a fun project when I was doing it, but there's no point re-inventing something that is way better than something you could ever make, especially when you can just hook into it with a custom script.