I certainly can make it, but the cost would be about the same as that Mayhem guy's price...but mine would be plasma cut rather than laser, and wouldn't include any of the hardware. So unless the cost of shipping kills the deal, it's probably best to just buy his.
The way I'm seeing it, for each wheel you'd need two full rings, plus 14 of the stackable spacer blocks. That's nice in that it uses the otherwise wasted interior of the rings, but certainly increases the cost. (compared to other companies who use that interior space to cut some of their other offerings, which they sell separately for more $$)