DIY Salad Bowl Beauty Dish
This one looks pretty darn OEM for DIY.
Reader Tom Seibert has a detailed post on how to make a large DIY beauty dish for speedlights, including a bracket that takes the strain off of your flash by not using it as part of the structural support.
In a second post, he shows how he was able to adjust the beam pattern of the dish to make for a much smoother light source.
It is an evolution of the Tejada beauty dish design, but pushes the dish size and introduces a more sturdy mounting system.
UPDATE: More on how to adjust the beam, here.