Here the link for the Notre Dame de Budapest pipe organ samples. Two different organs in two different cathedrals are included, with extensive breakdowns. I have heard only the GigaStudio 2.5 versions, which are quite exquisite. I understand that the GigaStudio 3.0 versions are even more lovely, but there may be some translation issues to Kontakt from those, if you don't have GigaStudio in your studio (if for nothing else, to downsave the 3.0 version files to something which can open in 2.x, and therefore translate easily to Kontakt).
So for Kontakt, I'd be looking more at the Giga 2.x version. Still a wonderful tool, by any standard.