"On-grade" examples:
---The "Mercier Collection" example was part of 55 cone group reportedly from a "Lake Tahoe find" around 1976 by Jim Mercier of Wisconsin. Around 1978, he sold all the beers to Dave Stark who continues to hold that "Deluxe" example. The Mercier example was the first time the brand was discovered by cone collectors active at the time, such as Dave Peck and wasn't pictured in BCU and Martell's books.
---Another example turned up oddly by a New Jersey breweriana collector Peter Lyndell (spelling?): he bought from the daughter of a Horton Brewing Co. employee about 12 cones. In the 1930's and '40's, occasionally mis-sent brands of cones would appear in pallets of new Horton Brewing cones and fortunately he saved some. There is a picture of just these cones, which shows a number of rare "low profile" brands: Leidig's Deluxe, Dawson Beer (w/card); National Beer; London Tavern Ale; brown ABC; among others, such as a high profile Red Top ale. Apparently also included (?) was an Ambassador cone that was sold earlier to Bob Gamer of NYC. Dick Caughey bought the remaining cones, and the Deluxe cone pictured passed through the hands of several collectors, and is now in Calif.
---A 3rd example was passed to Gene DiCicco in the early 1990's by one of his many sources in Calif., this time from the Bay Area, where apparently this Deluxe cone was found. The can is now in Tom Waggoner's collection.
-----"Outside" examples have appeared, but very infrequently - including one by Gene DiCicco from a source in Arizona. More recently in 2006 a good dumper with colors dug by Ed Scoglietti, and both these "finds" are important as confirms the brtand very likely had been filled with beer.
"On-grade" examples: Around 1976, a top shape example was also part of the "Mercier Collection". After learning about the label, in 1977 Bob Myers located three more in 1/1+ condition that had been found by a Highway Patrolman who flew a plane over Interstate 5. The pilot had seen them sitting on the inside of a wall in a half-basement of a "workshop" building that was behind a relative's pre-1920's home in a Calif. town. When getting the cans, Bob was shown the building to search it again, but no more cans were seen and still a question of who had left the 3 cans.
The Dutch Mill can pictured is from that "find".
A few other "inside" examples have appeared, such as a 1+ example Gene DiCicco found in a Sacramento antique shop, but not many others for maybe a total of 5-8 examples around?
"Outside" examples: have been found around Central Calif., such as two locations in the Santa Cruz mountains where Gene DiCicco found 6 Dutch Mill cones, and at another location, 3-4 Dutch Mill cones found in the "Leidig's dump" among the redwoods as described by Ed Scoglietti and others.
"On-grade" examples, around 8?:
The "Pilsener Style" by San Francisco Brewing was only rarely seen until 1977 when Ken Ostrow, now an active breweriana collector in the Boston area, located around 6, 1/1+ examples that Ken remembers well were unusually all opened with a knife. (Before that time, Bob Myers had seen two ("1-ish") examples: in a collection taken from the Golden West Bar in San Luis Obispo; and another at a now torn-down antique shop by the 101 freeway south of San Miguel.)
While attending glass blowing school in Oakland, Calif., Ken was searching throughout the Bay Area for beer cans, making a number of "finds" with the Leidig's flats being only one highlight. He was set up with a table at the Cow Palace and another seller there said he had around 6 Leidig's flats and some what are called now "grade 1-ish to 1+" Old Dutch ales from San Diego. Ken picked up 4 of the Leidig's flats and called Bob Myers who stopped by with his Leidig's Dutch Mill cans. With their two finds around May, 1977, an unusual coincidence had occurred: within a short interval they had located around 9 on-grade Leidig's cans from two different sources. Ken generously passed on his lead for the other Leidig's flats and Old Dutch ale cones to Bob Myers who bought the rest from Don Schmidt (mostly a Coca Cola collector from San Jose). Don said something about he had gotten them from a flea market source, who had some connection with the railroad, which might explains how Old Dutch ale cones from San Diego were found far north.
The Leidig's flat pictured is from Ken Ostrow's "find".
The "German Style": this is the rarer variation of the Liedig's flat top and pictures of this label show it was by Regal Amber Brewing. Gene DiCicco through his network found an approx. grade 1 example, which is now in Tom Waggoner's collection. Gene says he got a call on the can, made an appointment to see it, and later drove to the person's address. However no one was home, so Gene wondered what was going on? To pass the time, Gene happened to look in the window - there was the can on a table! Confirmation the caller actually did have what may be the cleanest example of the rarer Leidig's flat top variation, and the seller's delay returning home added suspense for Gene wanting to close the deal, which he did.
"Outside" examples of both variations of the flat top have been found by Gene DiCicco and others, but mostly of the "Pilsener Style" variety including several cases in the "Leidig's dump" described by Ed Scoglietti and others.