The bigger player in the problem is China.

Given the price of steel, you cheapest starting point might well be an existing vehicle frame that nearly matches your specs.

Since you drive a Mitsu, it might be cool to start with a junked 1st gen that has a good frame. Cut off the front, fabricate a front cross member and tongue assembly, and you have a good start. It will have a suspension in place, immediate wheel exchange with your tow vehicle, etc.

Jim Paget
88 YJ with a few changes

www.rrr4x4.com