(and maybe lesser-known examples by the sung Schumann, Mozart, Saint-Saëns ...

)
Carl Reinecke: Variationen über eine Sarabande von J.S. Bach, Op.24 (also, another work, his op. 52, is Bach-related?)
Arthur Foote: Transcription of a Bach Sarabande and Courante
Gyorgy Catoire: Concert transcription of J.S. Bach's Passacaglia in C minor for Piano
(The list expends exponentially into non-Romantic composers but that was not the question asked nor is this the right board

. Re Schumann I have too much trouble resisting mentioning although, again, not at all unsung unless you count the work in question - symphony no. 2's opening sounds to me much inspired by Bach as well, and what should happen to precede op.61 in the list of his published works but, well, the op. 60 studies on BACH...
and I forgot to mention Elgar, whose half of a famous exchange with Respighi of transcriptions was of the same Passacaglia in C minor, but this time for orchestra (well-enough known.) Respighi in turn had his Tre Corali, three chorale preludes for organ by Bach arr. for orchestra. (I consider Schoenberg a Romantic composer and he did himself, and of course his Bach arrangements are well-enough known, esp. that of the St. Anne Prelude and Fugue BWV552, but that's pushing it.)
Eric