Following are plans to build a buggy or off road vehicle. The plans provide a good starting point for the construction of your own buggy. Use your skills to adjust the plans to make a buggy that suits you.
Following are free buggy plans and instruction.
This buggy design is from Italy and uses a Honda motorcycle engine for power. It sits very low to the ground which is a negative for off road driving. As well, the roll cage should be made of tubular rather than square steel.
These buggy plans are very detailed, but I question whether it was ever built. It would make an excellent starting point for your own off road buggy vehicle.