Keith:
Thank you very much for the thread on 'True Grit'. It was most enlightening. I definitely heard Duke make that remark: 'What Judy Garland's little girl could have done with that part'.
Since there's no evidence that Liza Minnelli was ever in the running for the role, it seems likely that Duke formed this opinion in hindsight. 'Cahill' was filmed in the fall and early winter of 1972, which was the same year 'Cabaret' was released. Obviously, Duke had a high opinion of Liza Minnelli's acting talent.
Joe