Basically, it's a M7 or K47, a 6072 and a Triad transformer. I used one of Pearlman's recreations, and thought it sounded like a 47 with too much 10kHz and not enough bottom, and all the people familiar with the originals said that's what they sound like. But they were supposed to be much better for film sound than U47s.
If you have any questions about them, I'm sure Dave can help you out.
Ever since J Po used them, and then turned Jon Brion on to them, they became the cool thing.
It would be nice if you could take some good pics and upload them for some of our mic porn collections, though.