http://www.osb.org/intl/confed/bishops.html
Looks like there is more than one! Here is a list of cardinals:
Paul Augustin Cardinal Mayer OSB born at Altötting (Passau) 23 May 1911; professed in the Abbey of Metten 17 May 1931; priest 25 August 1935; Abbot of Metten 3 November 1966; abbatial blessing 10 December 1966; Secretary of the Congregation for Religious and Secular Institutes 8 September 1971; named Titular Archbishop of Satriano 6 January 1972; consecrated 13 February 1972 at Rome, in Saint Peter's Basilica, by His Holiness Pope Paul VI, assisted by Bernard Jan Cardinal Alfrink, Archbishop of Utrecht, and by William Cardinal Conway, Archbishop of Armagh; Pro-Prefect of the Congregation for the Sacraments and of the Congregation for Divine Worship 8 April 1984; Cardinal Deacon of Sant'Anselmo all'Aventino 25 May 1985; Prefect of the Congregation for the Sacraments and of the Congregation for Divine Worship 27 May 1985; resigned as Prefect of both Congregations 1 July 1988; President of the Pontifical Commission Ecclesia Dei from 2 July 1988 to 1 July 1991; Cardinal Priest of the Title of Sant'Anselmo all'Aventino 29 January 1996.
ugh nevermind, that is just one, I have the IQ of a toad.
That's the description of Cardinal Mayer's offices through the years. The rest of the list are bishops and archbishops, not full cardinals.
There's been some vague speculation that the first non-Cardinal since 655 years might be elected pope, in which case there are a whole lot more Benedictines to choose from, and bishops of Jewish origin, and even at least one Benedictine of Jewish origin. We shall see!