I do believe that the Fugue no. 10 in e minor, BWV 879, WTCII, has a whopping 48 note subject spanning 7 measures. It just keeps going and going. This is a 3 voice fugue (thank goodness it’s not more!) and of course takes 4 pages to play because each iteration takes MEASURES to get through. And the Prelude? Two parts, first part’s cadence ending on the dominant. Somewhere between today and the end of this project, I am going to count how many times JSB puts the Prelude into an early sonata form in WTCII. Already at least three times, yet WTCI only had this feature in the last prelude of the set of 24.