David,
As the designer, inventor, manufacturer and one of the retailer of the DRDT-2 I am flattered that you think so highly of the tool that you want to build one on your own. There is a relationship between time and money and you may not be spending as much money (TBD) building the DRDT-2 but you will be spending a lot of your own time.
The front end kit is being sold to those who have either the skills and tools to weld up a frame or have a friend who can. The machined and purchased parts in the front end kit are purchased in quantity to reduce costs to the customer. If you have the tools (IE mill, lathe, laser cutter, nickel plating) then you could in fact reproduce the tool. However it will take a fair amount of time.
Costs add up quickly when you have to buy minimum quantities of materials (case in point the steel used in the frame. I was able to find a short length of steel of the size I needed for my prototype, about $30. However short pieces are hard to come by and the steel is sold in minimum 20' lengths for about $160).
If you feel inclined to copy tool, go right ahead. However if you decide to publish instructions or plans on how to build one keep in mind that even though you could build one not everyone is properly equipped to do so.
The frame fabrication drawing is available on my website for your review.
www.experimentalaero.com