Tube Chassis 4x4

I am interested in seeing a built-from-scratch tube chassis rockcrawler. I myself am interested in some day building my own personally customized rockcrawler. I know there would be a lot of work invovled, but there is so many different parts and pieces on the market that it just makes my head spin when doing research on this subject. Problems being as simple as what thickness of tubing to use for the chassis, to problems about all the different gear ratios etc. I honestly don't even know what a good starting point would be on a project like this. I "Googled" the subject of "How to build a tube frame 4x4" and there is thousands of adds. It's kind of frustrating really. It would be interesting to see all the steps on how to go about building a complete 4x4 rig worthy or competing from ground up.