Quoniam tu solus sanctus - Cum Sancto Spiritu, Mass in B Minor (piano transcription) 

4:45 Cum Sancto Spiritu
[Score download] imslp.org/wiki/...
[Playlist] • Bach-Sun - Mass in B m...
[Transcription notes]
Quoniam tu solus sanctus: During the bass solo, one or both of the bassoon parts may be transposed to the treble clef for a better balance on the piano.
Cum Sancto Spiritu: The fugal passages are mostly identical to the original, but for the non-fugal passages a more dramatic style is adopted (e.g. block chords, cascading octaves). I usually avoid such a style for my Bach transcriptions, but I think there is no better alternative here.