As I go through my journey building an Electrathon vehicle, I thought it might be useful to include links to references that I found helpful. Maybe others might add their thoughts.
An excellent reference for tube notching or fishmouth cutting is at http://www.atomiczombie.com/Tutorial%20-%20Basic%20Fishmouth%20Cutting%20-%20Page%201.aspx
In general, there are many DIY bicycle frame build references that apply well to Electrathons.