Dai Vernon’s estate auction in 2010 would likely be where he got them from:
But I do see things of much greater value going for a lot less than that ebay auction (not to mention that for the price the deck could at least have been used by Vernon, not sealed
Buchinger Portrait :: 2800 :: 700-900
Buffum, Richard. Dai Vernon Interview Transcript :: 1400 :: 750-850
Bruce Cervon's private files - magic correspondence :: 2000 :: 500-600
Archive of Roger Klause/Bruce Cervon correspondence :: 1000 :: 250-350
18 packs of playing cards owned/used by Dai Vernon :: 1300 :: 200-300
Archive of 116 letters from Faucett Ross to Bruce Cervon :: 2200 :: 1000-1200
Dai Vernon's Academy of the Art of Magic Medallion :: 6500 :: 5000-6000
Bamberg, David (Fu-Manchu). Sepia-toned length portrait :: 2200 :: 300-400
Archive of Doug Henning/Dai Vernon ephemera. :: 4000 :: 350-550
Hofzinser, Johan Nepomuk. Hofzinser Playing Card :: 3400 :: 1000-1500
Dai Vernon's Address Book and book of routines :: 1100 :: 150-250
Dai Vernon's "Dead List." Handwritten by Vernon :: 2000 :: 300-500
First U.S. Passport of Dai Vernon. Issued in 1958 :: 1700 :: 150-250
Dai Vernon's Prop Case :: 16000 :: 5000-6000
Dai Vernon's personal scrapbook and photo album :: 6500 :: 5000-6000
Scrapbook from Dai Vernon's 82nd Birthday. Compile :: 1100 :: 100-200
Dai Vernon's personal 14K solid gold Spinning Coin :: 5000 :: 2000-3000
Servais Leroy's Magic Wand :: 950 :: 75-150
Mysto Magic Set No. 2010.., ca. 1921 :: 2800 :: 1000-1500
Triangular Production. Okito, circa 1946 :: 1500 :: 300-500
Ganson, Lewis. Dai Vernon's Inner Card Trilogy. :: 1000 :: 250-350
Archive of C. A. George Newmann manuscripts :: 1500 :: 100-200
Nicola's unique antique Chinese embroidered vest :: 3000 :: 500-1000
Contract for Okito's Employment with Thurston :: 3600 :: 400-600
Wallace the Magician 3 sheet poster :: 1300 :: 500-750
More details from the estate auction:
https://forums.geniimagazine.com/viewtopic.php?t=30208