Those are likely custom made. You can mimic this by using square-ish containers and rotating each new one by 45 degrees. It wont get you as many plants per stack, but it's at least a start and likely less expensive.
it may require a bit of work to get them to stack properly, but should meet the same purpose. That, or you could just go get a bunch of plastic cups and set them up how you like! I'm sure with a wooden frame they'd look about the same.
95% because I don't see this exact type on their website. But I think I saw this type on every expo they've been to in the last couple of years. They should be at Agritunity 2013 next weekend, so I can make sure if you're still looking.