I'm working at the R. Samson Raphael Hirsch Chair (Dept. of Jewish History in Bar-Ilan University, Ramat-Gan). The Chair holds the "Saenger Collection" - some 1000 manuscripts (mostly letters) in German and Hebrew from Rabbi Hirsch and his contemporaries. Now, one of the Hebrew manuscripts - from the time when Rabbi Hirsch was Landesrabbiner of Moravia - is addressed to a certain "Meir Sherkovitz" (using the Hebrew shin)in an unspecified Moravian community. Meir's sons Michael and Nathan, both merchants, are also mentioned. Furthermore, in the autobiography of Ignaz Briess, Schilderungen aus dem ehemaligen Ghettoleben a certain healer (a kind of physician who did not learn his profession at an university) named Zerkovitz of Prerau is mentioned. The text of this book may be found online at: www.schroefl.com/en/biographien/ignaz_briess/briess (chapter 10). If you want further details, please contact me by e-mail.