Anyone who builds chassis using chrome moly can whip out a great axle for you. They aren't brain surgery and a tube axle is every bit as strong as an I-beam axle. Plus, a race car is usually pretty light weight to start with.
Speaking of filming your work, if you get a chance watch Ed Roth's video of him building the L A Zoom show car in his 1-car garage. Never touches a tape measure, is tripping over junk all over the floor, mixes bondo and fiberglass resin in a dixie cup with his bare hands. Basically endorses how I have worked all my life!