I like that Millsteg! looks like what I was planning on building. Do you by chance have the measurements for it?
I don't remember the exact measurements off the top of my head but I used 2 inch square tubing, the mounts for each keggle and mash tun are 18 inch squares with 6 inch spacing between the top two. The total height is 24 inches I believe and the lower boil kettle sits 8 inches off the ground.
That's just off the top of my head but I can get the measurements for you exactly if you want.