Thank you for the info Rafael. I do hope that someday the 1955 Kna will see the light. And I completely agree–the Cluytens would be a great addition to the Parsifal discography! Which performances/recordings do you have in your collection? My collection so far:
Knappertsbusch - 1951, 1952, 1954, 1956, 1957, 1958, 1959, 1960, 1961, 1962, 1964
Barenboim - Teldec
Thielemann - DG
R. Kraus - Gebhardt
C. Krauss - Gebhardt
Kegel - Berlin Classics
Levine - Decca Box (The Wagner Operas)
Levine - DG (DVD)
Gatti - Sony (DVD)
Kubelik - Arts Archives
Solti - Decca Box
Jordan - Erato
Gergiev - Mariinsky
Jochum - Living Stage
Conlon - 2002 (Paris)
Way too few!! 
Still some major holes to fill: Boulez, Zweden, Kempe, Levine (DG-Domingo), Goodall, Kanowski, Karajan...
Best,
Paul
I have Parsifal from Bayreuth for every year from '51 to '72 plus '76, '85, '98 and 2012. The only Kna I am missing is the elusive '55. Others are
Buenos Aires 1969 Leinsdorf
Covent Garden 1971 Goodall
Covent Garden 2013 Pappano
Milan 1960
Munich 1964
Munich 1977 Stein
New York Met 1966
Paris 1954
Paris 1976 Stein
Rome 1950
Rome 1970
Salzburg 2013
Stockholm 1976 Segerstam
Venice 1970
Vienna 1961 Karajan
Studio
Gergiev, Goodall, Karajan, Kegel, Kubelik, Moralt, Solti and Thielemann
As you can see I'm quite fond of Parsifal myself. I'm also not too shy to admit I haven't listened to them all yet. Getting there though. I have a list in my wallet giving bare info on my Wagner operas which is why I am short on conductor details. I shall get back with the missing data.