What type of information are you looking for specifically? I've got a few of them. Not planning on selling them though. I've seen a pair of them go for crazy money before. But those were from Richard King and his stuff is super nice and brings a premium usually.

Here is a pic with Bonham using one. And also Richard's pic from his Ebay auction.

They shouldn't be that difficult to find as they were in production for a number of years. Roughly 1969- 1976 . In late 1975 the design of the bottom section was changed with the legs transitioning to a tubular style (although it was still the Atlas cymbal stand). This version stayed in production until approx. 1979-80 when the heavier Hercules line was introduced.

[COLOR="Black"]The model I am referring to was only made in 1969. They had the square indentations about 3-4 inches from the top, and were straight on the lower part of the leg. I heard that they were made especially for Bonzo and Carmine Appice, but they are in the Ludwig catalog. How many were made? Why are they so rare? Why did Ludwig change the design a year later? Which drummers used them?[/COLOR][/COLOR]

Here is another pic from Richard King. He says the Bonham base is the one on the right. Then the next version after that is on the left.

Sorry, I forgot the base section did evolve over time a bit, as did the middle section which had a more gradual taper from 1" to 5/8ths near the top on later models. Actually this stand model was in constant evolution during it's lifetime. It went through flat legs on a short base to a taller base tube to the tubular legged base with the swivel feet to the big rubber feet. The T bolts also changed from wing nuts to wing screws to T screws to the black plastic ones.

While the particular version of that stand that you're looking for isn't common it certainly wasn't made only for Appice and Bonham. I have one of them, possibly two, that I acquired locally at Music Go Round (and no, it isn't for sale). They are out there. Figure even just one year's production amounted to hundreds, if not thousands, of these stands at that time.