Kevin Crawford, of Sine Nomine Publishing, has started a personal project to research the book design practices of TSR. In it, he’s examining many of the publications that TSR have published in the past. He’s released the first draft of it to the public, and you can download the work-in-progress document as he works on it. He’s also releasing the InDesign resources he’s created for this so that other publishers can use this for their own free or commercial projects.
Kevin is one of the great boons to the OSR community who continually gives to and supports it with works like this, and he always creates fantastic gaming products. I’m looking forward to digging into this research properly when I get the chance.