Because someone had to take the time to figure out the geometry, and then build the jigs, aquire materials (shipping and handling) then there is the electricity, building costs (rental or mortgage or what not), insurance, tools, equipment and misc. supplies, also his time/effort. Cool stuff isn't just the materials that go into it, it is also all the rest of the work involved + materials. Do you go to work in the morning and tell your boss you only want to be paid material costs? It is a lot of $, but I don't see that it is out of line for what you would get. You try to copy that with nothing to go by other than these pictures and I would be fairly certain you'll spend twice that (remember your time is $ also).
Very nice rear suspension set-up Joe. I like my factory leaf suspension better personaly, but I do think that is cool. Will be interesting to hear what kind of performance change you'll get both road and 1/4mile. I don't suppose you ever had it on a skid pad to have some base line cornering information? Words like "it rode nice" or it "felt great" are not the same as real world performance figures, just like someone saying "that car feels like a ten second ride" but then they take it to a track and find out it is only a 14 second ride.