Just start with a real big chunk of aluminum and make friends with someone with a BIG CNC and....
Modern motorcycles can pull it off with extensive engineering but I doubt anyone is gonna make it happen on a homebuilt buggy, and if can stay together, it is gonna weigh more than it would in 4130. Think of how thick a normally steel 1/4" tab would be in aluminum to have the same shear strength. Probably like 1/2" aluminum tabs. Like Kfab said, unless you are starting with some cast subframes (obviously not realistic), I doubt it's success.